Physiology is a science that studies the mechanisms of functioning of an organism in its relationship with the environment (this is the science of the life of an organism), physiology is an experimental science and the main methods of physiological science are experimental methods. However, physiology as a science originated within medical science even before our era in Ancient Greece at the school of Hippocrates, when the main research method was the method of observation. Physiology emerged as an independent science in the 15th century thanks to the research of Harvey and a number of other natural scientists, and, starting from the end of the 15th - beginning of the 16th centuries, the main method in the field of physiology was the method of experiment. I.N. Sechenov and I.P. Pavlov made a significant contribution to the development of methodology in the field of physiology, in particular in the development of a chronic experiment.
Literature:
Human physiology. Kositsky
Korbkov. normal physiology.
Zimkin. Human physiology.
Human Physiology, ed. Pokrovsky V.N., 1998
Physiology of GND. Kogan.
Physiology of man and animals. Kogan. 2 t.
Ed. Tkachenko P.I. Human physiology. 3 t.
Ed. Nozdrochev. Physiology. General course. 2 t.
Ed. Kuraev. 3 v. Translated textbook? human physiology.
Observation method- the most ancient, originated in Dr. Greece, was well developed in Egypt, on Dr. East, Tibet, China. The essence of this method lies in the long-term observation of changes in the functions and states of the body, fixing these observations and, if possible, comparing visual observations with changes in the body after opening. In Egypt, during mummification, corpses were opened, the priest's observations of the patient: changes in the skin, depth and frequency of breathing, the nature and intensity of discharge from the nose, mouth, as well as the volume and color of urine, its transparency, the amount and nature of the excreted feces, its color, pulse rate and other indicators, which were compared with changes in the internal organs, were recorded on papyrus. Thus, already by changing the feces, urine, sputum, etc. excreted by the body. it was possible to judge a violation of the functions of one or another organ, for example, if the feces are white, it is permissible to assume a violation of the functions of the liver, if the feces are black or dark, then it is possible to assume gastric or intestinal bleeding. Changes in the color and turgor of the skin, swelling of the skin, its character, color of the sclera, sweating, trembling, etc. served as an additional criterion.
Hippocrates attributed the nature of behavior to the observed signs. Thanks to his careful observations, he formulated the doctrine of temperament, according to which all of humanity is divided into 4 types according to the characteristics of behavior: choleric, sanguine, phlegmatic, melancholic, but Hippocrates was mistaken in the physiological justification of the types. Each type was based on the ratio of the main body fluids: sangvi - blood, phlegm - tissue fluid, cholea - bile, melancholea - black bile. The scientific theoretical substantiation of temperaments was given by Pavlov as a result of lengthy experimental studies and it turned out that temperament is based not on the ratio of fluids, but on the ratio of nervous processes of excitation and inhibition, the degree of their severity and the predominance of one process over another, as well as the rate of change of one process by others.
The method of observation is widely used in physiology (especially in psychophysiology), and at present the method of observation is combined with the method of chronic experiment.
Experiment Method. A physiological experiment, in contrast to simple observation, is a purposeful intervention in the current administration of the organism, designed to clarify the nature and properties of its functions, their relationships with other functions and with environmental factors. Also, the intervention often requires surgical preparation of the animal, which can wear: 1) acute (vivisection, from the word vivo - living, sekcia - secu, i.e. secu for the living), 2) chronic (experimental-surgical) forms.
In this regard, the experiment is divided into 2 types: acute (vivisection) and chronic. A physiological experiment allows you to answer the questions: what happens in the body and how it happens.
Vivisection is a form of experiment performed on an immobilized animal. For the first time, vivisection began to be used in the Middle Ages, but began to be widely introduced into physiological science in the Renaissance (XV-XVII centuries). Anesthesia at that time was not known and the animal was rigidly fixed by 4 limbs, while it experienced torment and uttered heartbreaking cries. The experiments were carried out in special rooms, which the people dubbed "devilish". This was the reason for the emergence of philosophical groups and currents. Animalism (trends, promoting a humane attitude towards animals and advocating an end to animal abuse, animalism is being promoted at the present time), vitalism (advocated that experiments were not carried out on non-anesthetized animals and volunteers), mechanism (identified correctly occurring in an animal with processes in inanimate nature, prominent representative mechanism was the French physicist, mechanic and physiologist Rene Descartes), anthropocentrism.
Beginning in the 19th century, anesthesia began to be used in acute experiments. This led to a violation of the regulatory processes on the part of the higher processes of the central nervous system, as a result, the integrity of the body's response and its connection with the external environment are violated. Such use of anesthesia and surgical harassment during vivisection introduces uncontrolled parameters into the acute experiment, which are difficult to take into account and foresee. An acute experiment, like any experimental method, has its advantages: 1) vivisection is one of the analytical methods that makes it possible to simulate different situations 2) vivisection makes it possible to obtain results in a relatively short time; and disadvantages: 1) in an acute experiment, consciousness is turned off when anesthesia is used and, accordingly, the integrity of the body's response is violated, 2) the body's connection with the environment is disrupted in cases of anesthesia, 3) in the absence of anesthesia, there is an inadequate release of stress hormones and endogenous (produced by inside the body) morphine-like substances of endorphins, which have an analgesic effect.
All this contributed to the development of a chronic experiment - long-term observation after an acute intervention and restoration of relationships with the environment. Advantages of a chronic experiment: the body is as close as possible to the conditions of intensive existence. Some physiologists attribute the shortcomings of a chronic experiment to the fact that the results are obtained in a relatively long time.
The chronic experiment was first developed by the Russian physiologist I.P. Pavlov, and, since the end of the 18th century, has been widely used in physiological research. A number of methodological techniques and approaches are used in the chronic experiment.
The method developed by Pavlov is a method of imposing fistulas on hollow organs and on organs that have excretory ducts. The ancestor of the fistula method was Basov, however, when a fistula was applied by his method, the contents of the stomach fell into the test tube along with digestive juices, which made it difficult to study the composition of gastric juice, the stages of digestion, the speed of digestion processes and the quality of the separated gastric juice for different food composition.
Fistulas can be superimposed on the stomach, ducts of the salivary glands, intestines, esophagus, etc. The difference between the Pavlovian fistula and the Basovian one is that Pavlov applied the fistula to the “small ventricle”, which was artificially made surgically and retained digestive and humoral regulation. This allowed Pavlov to reveal not only the qualitative and quantitative composition of gastric juice for food intake, but also the mechanisms of nervous and humoral regulation of digestion in the stomach. In addition, this allowed Pavlov to identify 3 stages of digestion:
conditioned reflex - with it, appetizing or "ignition" gastric juice is released;
unconditional reflex phase - gastric juice is secreted to incoming food, regardless of its quality composition, because in the stomach there are not only chemoreceptors, but also non-chemoreceptors that react to the volume of food,
intestinal phase - after food enters the intestines, digestion is enhanced.
Heterogeneous neurovascular or neuromuscular anasthenoses. This is a change in the effector organ in the genetically determined nervous regulation of functions. Carrying out such anasthenoses reveals the absence or presence of plasticity of neurons or nerve centers in the regulation of functions, i.e. whether the sciatic nerve with the remainder of the spine can control the respiratory muscles.
In neurovascular anasthenoses, the effector organs are the blood vessels and, accordingly, the chemo- and baroreceptors located in them. Anasthenoses can be performed not only on one animal, but also on different animals. For example, if neurovascular anastenosis is performed in two dogs on the carotid zone (branching of the arch of the carotid artery), then it is possible to identify the role of various parts of the central nervous system in the regulation of respiration, hematopoiesis, and vascular tone. At the same time, the mode of inhaled air is changed in a bottom dog, and the regulation is seen in another.
Transplantation of various organs. Replanting and removal of organs or various parts of the brain (extirpation). As a result of the removal of an organ, a hypofunction of a particular gland is created; as a result of replanting, a situation of hyperfunction or an excess of hormones of a particular gland is created.
Extirpation of various parts of the brain and cerebral cortex reveal the functions of these departments. For example, when the cerebellum was removed, its participation in the regulation of movement, in maintaining posture, and statokinetic reflexes was revealed.
Removal of various sections of the cerebral cortex allowed Brodman to map the brain. He divided the bark into 52 fields according to functional items.
The method of transection of the spinal cord. Allows you to identify the functional significance of each department of the central nervous system in the regulation of somatic and visceral functions of the body, as well as in the regulation of behavior.
Implantation of electrons in various parts of the brain. Allows you to identify the activity and functional significance of a particular nervous structure in the regulation of body functions (motor functions, visceral functions and mental ones). The electrodes implanted in the brain are made of inert materials (that is, they must be intoxicant): platinum, silver, palladium. The electrodes allow not only to reveal the function of one or another area, but vice versa, to register in which part of the brain the appearance causes a potential (BT) in response to certain functional functions. Microelectrode technology gives a person the opportunity to study the physiological foundations of the psyche and behavior.
Cannula implantation (micro). Perfusion is the passage of solutions of various chemical composition through our component or the presence of metabolites in it (glucose, PVC, lactic acid) or the content of biologically active substances(hormones, neurohormones, endorphins, enkephamins, etc.). The cannula allows you to inject solutions with different contents into a particular area of the brain and observe changes in functional activity on the part of the motor apparatus, internal organs or behavior, psychological activity.
Microelectrode technology and conjugation are used not only in animals, but also in humans during brain surgery. In most cases, this is done for diagnostic purposes.
Introduction of labeled atoms and subsequent observation on a positron emission tomograph (PET). Most often, auro-glucose labeled with gold (gold + glucose) is administered. According to Greene's figurative expression, ATP is the universal energy donor in all living systems, and in the synthesis and resynthesis of ATP, glucose is the main energy substrate (ATP resynthesis can also occur from creatine phosphate). Therefore, the amount of glucose consumed is used to judge the functional activity of a particular part of the brain, its synthetic activity.
Glucose is consumed by cells, while gold is not utilized and accumulates in this area. According to the multi-active gold, its amount is judged on the synthetic and functional activity.
stereotactic methods. These are methods in which surgical operations are performed to implant electrodes in a certain area of the brain in accordance with the stereotaxic atlas of the brain, followed by recording of assigned fast and slow biopotentials, with recording of evoked potentials, as well as recording of EEG, myograms.
When setting new goals and objectives, one and the same animal can be used for a long time of observation, changing the location of microelements or perfusing different areas of the brain or organs with various solutions containing not only biologically active substances, but also metatholites, energy substrates (glucose, creotine phosphate, ATP ).
biochemical methods. This is a large group of methods by which in circulating fluids, tissues, and sometimes organs, the level of cations, anions, unionized elements (macro and microelements), energy substances, enzymes, biologically active substances (hormones, etc.) is determined. These methods are applied either in vivo (in incubators) or in tissues that continue to secrete and synthesize produced substances into the incubation medium.
Biochemical methods make it possible to evaluate the functional activity of a particular organ or part of it, and sometimes whole system organs. For example, the level of 11-OCS can be used to judge the functional activity of the fascicular zone of the adrenal cortex, but the level of 11-OCS can also be used to judge the functional activity of the hypothalamic-pituitary-adrenal system. In general, since 11-OCS is the end product of the peripheral link of the adrenal cortex.
Methods for studying the physiology of GNI. The mental work of the brain for a long time remained inaccessible to natural science in general and to physiology in particular. Mainly because it was judged by sensations and impressions, i.e. using subjective methods. Success in this field of knowledge was determined when mental activity (GNA) began to be judged using an objective method of conditioned reflexes of varying complexity of development. At the beginning of the 20th century, Pavlov developed and proposed a method for developing conditioned reflexes. On the basis of this technique, additional methods for studying the properties of GNI and the localization of GNI processes in the brain are possible. Of all the techniques, the following are the most commonly used:
Testing the possibility of forming various forms of conditioned reflexes (to pitch, to color, etc.), which allows us to judge the conditions of primary perception. Comparisons of these boundaries in animals different types allows you to identify: in what direction was the evolution of the sensory systems of the GNI.
Ontogenetic study of conditioned reflexes. The complex behavior of animals of different ages, when studied, makes it possible to establish what in this behavior is innate and what is acquired. For example, Pavlov took puppies of the same litter and fed some with meat and others with milk. Upon reaching adulthood, he developed conditioned reflexes in them, and it turned out that in those dogs that received milk from childhood, conditioned reflexes were developed for milk, and in those dogs that were fed meat from childhood, conditioned reflexes were easily developed for meat. Thus, dogs do not have a strict preference for the type of carnivorous food, the main thing is that it be complete.
Phylogenetic study of conditioned reflexes. Comparing the properties of the conditioned reflex activity of animals of different levels of development, one can judge in what direction the evolution of GNI is going. For example, it turned out that the rate of formation of conditioned reflexes sharply from invertebrates and vertebrates, changes relatively finely throughout the entire history of the development of vertebrates and abruptly reaches the ability of a person to immediately connect coincident events (imprinting), imprinting is also characteristic of brood birds (ducklings hatched from eggs can to follow any object: a chicken, a person, and even a moving toy.The transitions between invertebrates - vertebrates, vertebrates - humans reflected the critical stages of evolution associated with the emergence and development of GNA (in insects, the nervous system is of a non-cellular type, in the coelenterates - of the reticular type , in vertebrates - a tubular type, in birds ball ganglia appear, some cause a high development of conditioned reflex activity.In humans, the cerebral cortex is well developed, which causes the jump.
Ecological study of conditioned reflexes. The action potential arising in the nerve cells involved in the formation of reflex connections makes it possible to identify the main links of the conditioned reflex.
It is especially important that bioelectronic indicators make it possible to observe the formation of a conditioned reflex in the structures of the brain even before it appears in the motor or vegetative (visceral) reflexes of the body. Direct stimulation of the nervous structures of the brain makes it possible to set up model experiments on the formation of nerve connections between artificial foci of excitation. It is also possible to directly determine how the excitability of the nervous structures participating in it changes during a conditioned reflex.
Pharmacological action in the formation or alteration of conditioned reflexes. By introducing certain substances into the brain, it is possible to determine what effect they have on the rate and strength of the formation of conditioned reflexes, on the ability to remake the conditioned reflex, which makes it possible to judge the functional mobility of the central nervous system, as well as the functional state of cortical neurons and their performance. For example, it was found that caffeine provides the formation of conditioned reflexes when nerve cells are highly efficient, and when their performance is low, even a small dose of caffeine makes excitation unbearable for nerve cells.
Creation of an experimental pathology of conditioned reflex activity. For example, surgical removal of the temporal lobes of the cerebral cortex leads to mental deafness. The method of extirpation reveals the functional significance of areas of the cortex, subcortex and brain stem regions. In the same way, the localization of the cortical ends of the analyzers is determined.
Modeling the processes of conditioned reflex activity. Pavlov also attracted mathematicians in order to express by a formula the quantitative dependence of the formation of a conditioned reflex on the frequency of its reinforcement. It turned out that in most healthy animals, including humans, a conditioned reflex was developed in healthy people after 5 reinforcements with an unconditioned stimulus. This is especially important in service dog breeding and in the circus.
Comparison of psychological and physiological manifestations of the conditioned reflex. Support voluntary attention, flight, learning efficiency.
Comparison of psychological and physiological manifestations with bioelements and morphological with biokinetic: production of memory proteins (S-100) or areas of biologically active substances in the formation of conditioned reflexes. It has been proven that if vasoprocession is introduced, then conditioned reflexes are developed faster (vasopressure is a neuro-hormone produced in the hypothalamus). Morphological changes in the structure of a neuron: a naked neuron at birth and with denurites in an adult.
Lab #1
Foreword
Chapter 1. Physiology and its significance for medicine. G. I. Kositsky
Development of physiological research methods
Conclusion
SECTION I. GENERAL PHYSIOLOGY.
Introduction. G. I. Kositsky
Chapter 2. Physiology of excitable tissues. B. I Khodorov
resting potential
action potential
Mechanisms of stimulation of a cell (fiber) by electric current
Chapter 3. Muscle contraction. B. I. Khodorov
Skeletal muscles
Smooth muscles
Chapter 4. Conduction of a nerve impulse and neuromuscular transmission. B. I. Khodorov
Conducting a nerve impulse
neuromuscular transmission
Trophic function of motor nerve fibers and their endings
Features of neuromuscular transmission of excitation and smooth muscles
Conclusion. G. I. Kositsky
SECTION II. MECHANISMS OF REGULATION OF PHYSIOLOGICAL PROCESSES.
Introduction by G. I. Kositsky
Chapter 5. General physiology of the central nervous system. A. I. Shapovalov
neural theory
Communication mechanisms between neurons
mediator release process
Chemical mediators
Excitation in the central nervous system
Inhibition in the central nervous system
Integration of synaptic influences
Reflex activity of the CHC
Association of neurons in the nerve center
Chapter 6. Particular physiology of the central nervous system. A. I. Shapovalov
Spinal cord
Hind brain
midbrain
Cerebellum
diencephalon
forebrain
The cerebral cortex
Movement coordination. V. S. Gurfinkel and R. S. Person
Blood supply to the brain and cerebrospinal fluid. E. B. Babsky
Chapter 7 Nervous regulation vegetative functions. E. B. Babsky and G. I. Kositsky
The general plan of the structure and the main physiological properties of the autonomic nervous system
Autonomic innervation of tissues and organs
Autonomic reflexes and centers of regulation of autonomic functions
Chapter 8. Hormonal regulation of physiological functions. G. I. Kositsky
Internal secretion of the pituitary gland
Internal secretion of the thyroid gland
Internal secretion of the parathyroid glands
Internal secretion of the pancreas
Internal secretion of the adrenal glands
Internal secretion of the gonads
Hormones of the placenta
Internal secretion of the epiphysis
tissue hormones
Conclusion. G. I. Kositsky
SECTION III. INTERNAL ENVIRONMENT OF THE ORGANISM; SYSTEMS AND BODIES. PROCESSES INVOLVED IN MAINTAINING ITS CONSTANTITY.
Introduction. G. I. Kositsky
Chapter 9. Physiology of the blood system. G. I. Kositsky
Composition, quantity and physico-chemical properties of blood
Blood clotting. V. P. Skipetrov
Blood groups
Formed elements of blood
Hematopoiesis and regulation of the blood system
Chapter 10 E. B. Babsky, A. A. Zu6kov, G. I. Kositsky
activity of the heart
Blood vessels
Chapter 11 V. D. Glebovsky, G. I. Kositsky
external respiration
Gas exchange in the lungs
Gas transport by blood
Gas exchange in tissues
Breathing regulation
Chapter 12 E. B. Babsky, G. F. Korotko
Physiological basis of hunger and satiety
Essence of digestion and classification of digestive processes
Digestion in the mouth
Digestion in the stomach
Digestion in the small intestine
Digestion in the large intestine
Periodic activity of the digestive organs
Suction
Chapter 13 Nutrition. E. B. Babsky, V. M. Pokrovsky
Metabolism
Energy conversion and general metabolism
Nutrition
Chapter 14 E. B. Babsky, V. M. Pokrovsky
Chapter 15 Yu. V. Natochin
Kidneys and their function
The process of urination
homeostatic kidney function
Urination and urination
Consequences of kidney removal and artificial kidney
Age features structures and functions of the kidneys
Conclusion. G. I. Kositsky
SECTION IV. RELATIONSHIP OF THE ORGANISM AND THE ENVIRONMENT.
Introduction. G. I. Kositsky
Chapter 16. Physiology of analyzers. E. B. Babsky, I. A. Shevelev
General physiology of analyzers
Particular physiology of analyzers
Chapter 17 E. B. Babsky, A. B. Kogan
general characteristics and properties of conditioned reflexes
Methodology for studying conditioned reflexes
Temporary connection closure mechanisms
Inhibition of conditioned reflexes
Analysis and synthesis of stimuli in the cerebral cortex
Types of higher nervous activity, neuroses
Chapter 18 E. B. Babsky, G. I. Kositsky
First and second signal systems
Mechanisms of purposeful human activity
Sleep physiology
The relationship between the processes of higher nervous activity that ensure the emergence of consciousness and subconsciousness
Physiology of emotions
Chapter 19. Elements of labor physiology, mechanisms of training and adaptation. G. I. Kositsky
Physiology of physical labor
Physiological features of nervously stressful labor
Fatigue and physiological measures to prevent it
Training Mechanisms
Adaptation mechanisms
Conclusion. G. I. Kositsky
Appendix. Basic quantitative physiological indicators
Bibliography
Subject index
-- [ Page 1 ] --
EDUCATIONAL LITERATURE
For medical students
Physiology
human
Edited by
Corresponding Member USSR Academy of Medical Sciences G. I. KOSITSKY
THIRD EDITION,
RECYCLED
AND ADDITIONAL
Approved by the Main Directorate of Education
institutions of the Ministry of Health
the protection of the USSR as a textbook
for medical students
Moscow "Medicine" 1985
E. B. BABSKY, V. D. GLEBOVSKY, A. B. KOGAN, G. F. KOROTKO,
G. I. Kositsky, V. M. Pokrovsky, Yu. V. Natochin, V. P.
SKIPETROV, B. I. HODOROV, A. I. SHAPOVALOV, I. A. SHEVELEV Reviewer I. D. Boenko, prof., head. Department of Normal Physiology, Voronezh Medical Institute. N. N. Burdenko Human Physiology / Ed. G. I. Kositsky. - F50 3rd ed., Revised. and add. - M.: Medicine, 1985. 544 p., ill.
In lane: 2 p. 20 k. 15,000 copies.
The third edition of the textbook (the second was published in 1972) was written in accordance with the achievements modern science. New facts and concepts are presented, new chapters are included: "Peculiarities of higher nervous activity of a person", "Elements of labor physiology, mechanisms of training and adaptation", sections covering questions of biophysics and physiological cybernetics are expanded. Nine chapters of the textbook were written anew, the rest were largely revised.
The textbook complies with the program approved by the USSR Ministry of Health and is intended for students of medical institutes.
2007020000-241 BBK 28. 039(01) - Publishing House "Medicine", FOREWORD Twelve years have passed since the previous edition of the textbook "Human Physiology".
The responsible editor and one of the authors of the book, Academician of the Academy of Sciences of the Ukrainian SSR E.B.
Shapovalov and prof. Yu.V. V.D. Glebovsky (Head of the Department of Physiology of the Leningrad Pediatric Medical Institute), prof. A.B.Kogan (Head of the Department of Human and Animal Physiology and Director of the Institute of Neurocybernetics of the Rostov State University), prof. G. F. Korotko (Head of the Department of Physiology of the Andijan Medical Institute), prof. V.M. Pokrovsky (Head of the Department of Physiology of the Kuban Medical Institute), prof. B.I. Khodorov (head of the laboratory of the Institute of Surgery named after A.V. Vishnevsky of the USSR Academy of Medical Sciences), prof. I. A. Shevelev (Head of Laboratory, Institute of Higher Nervous Activity and Neurophysiology, USSR Academy of Sciences).
In the past, there has been a large number of new facts, views, theories, discoveries and directions of our science. In this regard, 9 chapters in this edition had to be written anew, and the remaining 10 chapters were revised and supplemented. At the same time, to the extent possible, the authors tried to preserve the text of these chapters.
The new sequence of presentation of the material, as well as its combination into four main sections, is dictated by the desire to give the presentation logical harmony, consistency and, as far as possible, avoid duplication of material.
The content of the textbook corresponds to the program in physiology, approved in the year. The criticisms of the project and the program itself expressed in the resolution of the Bureau of the Department of Physiology of the USSR Academy of Sciences (1980) and at the All-Union Conference of Heads of Departments of Physiology of Medical Universities (Suzdal, 1982) were also taken into account. In accordance with the program, chapters were introduced into the textbook that were absent in the previous edition: “Peculiarities of higher nervous activity of a person” and “Elements of labor physiology, mechanisms of training and adaptation”, as well as expanded sections covering issues of particular biophysics and physiological cybernetics. The authors took into account the fact that in 1983 a biophysics textbook for students of medical institutes was published (ed.
prof. Yu.A. Vladimirova) and that the elements of biophysics and cybernetics are set out in the textbook by prof. A.N. Remizova "Medical and biological physics".
Due to the limited volume of the textbook, it was necessary, unfortunately, to omit the chapter "History of Physiology", as well as excursions into history in separate chapters. Chapter 1 gives only sketches of the formation and development of the main stages of our science and shows its significance for medicine.
Our colleagues provided great assistance in the creation of the textbook. At the All-Union Conference in Suzdal (1982), the structure was discussed and approved, and valuable wishes were expressed regarding the content of the textbook. Prof. VP Skipetrov revised the structure and edited the text of the 9th chapter and, in addition, wrote its sections relating to blood coagulation. Prof. V. S. Gurfinkel and R. S. Person wrote subsection 6 “Regulation of movements”. Assoc. NM Malyshenko presented some new materials for chapter 8. Prof. IDBoenko and his collaborators expressed many useful comments and wishes as reviewers.
Employees of the Department of Physiology II MOLGMI named after N. I. Pirogov prof. L. A. Mipyutina Associate Professors I. A. Murashova, S. A. Sevastopolskaya, T. E. Kuznetsova, Candidate of Medical Sciences "Mpngush" and L. M. Popova took part in the discussion of the manuscript of some chapters.
I would like to express our deep gratitude to all these comrades.
The authors are fully aware that in such a difficult matter as the creation of a modern textbook, shortcomings are inevitable and therefore they will be grateful to everyone who expresses critical comments and wishes about the textbook.
Corresponding Member of the USSR Academy of Medical Sciences, prof. GI KOSI1DKIY Chapter PHYSIOLOGY AND ITS SIGNIFICANCE Physiology (from the Greek physis - nature and logos - teaching) is the science of the vital activity of the whole organism and its individual parts: cells, tissues, organs, functional systems. Physiology seeks to reveal the mechanisms of the implementation of the functions of a living organism, their relationship with each other, regulation and adaptation to the external environment, origin and formation in the process of evolution and individual development individuals.
Physiological regularities are based on data on the macro- and microscopic structure of organs and tissues, as well as on biochemical and biophysical processes occurring in cells, organs and tissues. Physiology synthesizes specific information obtained by anatomy, histology, cytology, molecular biology, biochemistry, biophysics and other sciences, combining them into a single system of knowledge about the body.
Thus, physiology is a science that implements a systematic approach, i.e.
study of the organism and all its elements as systems. Systems approach orients the researcher, first of all, towards revealing the integrity of the object and the mechanisms that ensure it, i.e. to identify the diverse types of connections of a complex object and reduce them into a single theoretical picture.
The object of study of physiology is a living organism, the functioning of which as a whole is not the result of a simple mechanical interaction of its constituent parts. The integrity of the organism does not arise as a result of the influence of some supra-material essence, which unquestioningly subjugates all the material structures of the organism. Similar interpretations of the integrity of the organism existed and still exist in the form of a limited mechanistic (metaphysical) or no less limited idealistic (vitalistic) approach to the study of life phenomena.
The errors inherent in both approaches can only be overcome by studying these problems from a dialectical-materialist standpoint. Therefore, the regularities of the activity of an organism as a whole can be understood only on the basis of a consistently scientific worldview. For its part, the study of physiological laws provides rich factual material illustrating a number of propositions of dialectical materialism. The connection between physiology and philosophy is thus two-way.
Physiology and Medicine By revealing the main mechanisms that ensure the existence of an integral organism and its interaction with the environment, physiology makes it possible to find out and investigate the causes, conditions, and nature of disturbances in the activity of these mechanisms during illness. It helps to determine the ways and means of influencing the body, with the help of which it is possible to normalize its functions, i.e. restore health.
Therefore, physiology is the theoretical basis of medicine, physiology and medicine are inseparable. The doctor assesses the severity of the disease according to the degree of functional impairment, i.e. by the magnitude of the deviation from the norm of a number of physiological functions. Currently, such deviations are measured and quantified. Functional (physiological) studies are the basis of clinical diagnostics, as well as a method for assessing the effectiveness of treatment and prognosis of diseases. Examining the patient, establishing the degree of violation of physiological functions, the doctor sets himself the task of returning these functions to normal.
However, the significance of physiology for medicine is not limited to this. The study of the functions of various organs and systems made it possible to simulate these functions with the help of instruments, devices and devices created by human hands. In this way, an artificial kidney (hemodialysis machine) was constructed. Based on the study of the physiology of the heart rhythm, an apparatus for electrical stimulation of the heart was created, which ensures normal cardiac activity and the possibility of returning to work in patients with severe heart damage. An artificial heart and artificial circulation devices (heart-lung machines) were made, which make it possible to turn off the patient's heart for the duration of a complex operation on the heart. There are defibrillation machines that restore normal cardiac activity in fatal violations of the contractile function of the heart muscle.
Research in the field of respiratory physiology made it possible to design an apparatus for controlled artificial respiration (“iron lungs”). Devices have been created with the help of which it is possible to turn off the patient's breathing for a long time under conditions of operations or to maintain the life of the body for years in case of damage to the respiratory center. Knowledge of the physiological laws of gas exchange and transport of gases helped to create installations for hyperbaric oxygenation. It is used in fatal lesions of the blood system, as well as the respiratory and cardiovascular systems.
Based on the laws of brain physiology, methods have been developed for a number of complex neurosurgical operations. Thus, electrodes are implanted into the cochlea of a deaf person, through which electrical impulses from artificial sound receivers arrive, which restores hearing to a certain extent.
These are only a very few examples of the use of the laws of physiology in the clinic, but the significance of our science goes far beyond the limits of medical medicine alone.
The role of physiology in ensuring human life and activity in various conditions The study of physiology is necessary for scientific substantiation and creation of conditions healthy lifestyle life, preventive disease. Physiological regularities are the basis of the scientific organization of labor in modern production. Physiology has made it possible to develop a scientific substantiation of various modes of individual training and sports loads that underlie modern sports achievements. And not only sports. If you need to send a person into space or lower him into the depths of the ocean, undertake an expedition to the north and south poles, reach the peaks of the Himalayas, master the tundra, taiga, desert, place a person in extremely high or low temperatures, move it to different time zones or climatic conditions, then physiology helps to substantiate and provide everything necessary for human life and work in such extreme conditions.
Physiology and Technology Knowledge of the laws of physiology was required not only for the scientific organization and increasing the productivity of labor. Over billions of years of evolution, nature, as is known, has reached the highest perfection in the design and control of the functions of living organisms. The use in technology of the principles, methods and methods operating in the body opens up new prospects for technical progress. Therefore, at the intersection of physiology and technical sciences, a new science, bionics, was born.
Advances in physiology contributed to the creation of a number of other areas of science.
W. HARVEY (1578--1657) DEVELOPMENT OF METHODS OF PHYSIOLOGICAL RESEARCH Physiology was born as an experimental science. It obtains all data by direct study of the vital processes of animal and human organisms. The founder of experimental physiology was the famous English physician William Harvey.
“Three hundred years ago, in the midst of the deep darkness and now hard to imagine confusion that reigned in the ideas about the activities of animal and human organisms, but illuminated by the inviolable authority of the scientific classical heritage, physician William Harvey peeped one of the most important functions of the body - blood circulation and thereby laid the foundation new department of exact human knowledge of animal physiology,” wrote I.P. Pavlov. However, for two centuries after the discovery of the blood circulation by Harvey, the development of physiology was slow. Relatively few fundamental works of the 17th-18th centuries can be listed. These are the discovery of capillaries (Malpighi), the formulation of the principle of reflex activity of the nervous system (Descartes), the measurement of blood pressure (Health), the formulation of the law of conservation of matter (M.V. Lomonosov), the discovery of oxygen (Priestley) and the generality of combustion and gas exchange processes ( Lavoisier), the discovery of "animal electricity", i.e.
the ability of living tissues to generate electrical potentials (Galvani), and some other works.
Observation as a method of physiological research. The relatively slow development of experimental physiology during the two centuries following Harvey's work is explained by the low level of production and development of natural science, as well as by the difficulties of studying physiological phenomena through their ordinary observation. Such a methodological technique was and remains the cause of numerous errors, since the experimenter must conduct the experiment, see and remember a lot . Harvey's words eloquently testify to the difficulties that the technique of simple observation of physiological phenomena creates: “The speed of cardiac movement does not allow one to distinguish how systole and diastole occur, and therefore it is impossible to know at what moment and in which part expansion and contraction occurs. Indeed, I could not distinguish systole from diastole, since in many animals the heart shows up and disappears in the twinkling of an eye, with the speed of lightning, so that it seemed to me once here systole, and here - diastole, another time - vice versa. Everything is different and inconsistent.”
Indeed, physiological processes are dynamic phenomena. They are constantly evolving and changing. Therefore, only 1-2 or, at best, 2-3 processes can be observed directly. However, in order to analyze them, it is necessary to establish the relationship of these phenomena with other processes that, with this method of research, remain unnoticed. In this connection, simple observation of physiological processes as a research method is a source of subjective errors. Usually, observation makes it possible to establish only the qualitative side of phenomena and makes it impossible to study them quantitatively.
An important milestone in the development of experimental physiology was the invention of the kymograph and the introduction of the method of graphic recording of blood pressure by the German scientist Karl Ludwig in 1843.
Graphic registration of physiological processes. The method of graphic registration marked a new stage in physiology. It made it possible to obtain an objective record of the process under study, minimizing the possibility of subjective errors. In this case, the experiment and analysis of the phenomenon under study could be carried out in two stages.
During the experiment itself, the task of the experimenter was to obtain high-quality records - curves. The data obtained could be analyzed later, when the experimenter's attention was no longer diverted to the experiment.
The method of graphic recording made it possible to record simultaneously (synchronously) not one, but several (theoretically an unlimited number) of physiological processes.
Quite soon after the invention of arterial pressure recording, methods for recording the contraction of the heart and muscles (Engelman) were proposed, a method of air transmission (Marey's capsule) was introduced, which made it possible to record, sometimes at a considerable distance from the object, a number of physiological processes in the body: respiratory movements of the chest and abdominal cavity, peristalsis and changes in the tone of the stomach, intestines, etc. A method was proposed for recording vascular tone (Mosso plethysmography), changes in volume, various internal organs - oncometry, etc.
Studies of bioelectric phenomena. An extremely important direction in the development of physiology was marked by the discovery of "animal electricity". The classic "second experiment" by Luigi Galvani showed that living tissues are a source of electrical potentials that can act on the nerves and muscles of another organism and cause muscle contraction. Since then, for almost a century, the only indicator of the potentials generated by living tissues (bioelectric potentials) has been the neuromuscular preparation of the frog. He helped discover the potentials generated by the heart during its activity (experiment of Kölliker and Müller), as well as the need for continuous generation of electrical potentials for constant muscle contraction (experiment of Mateuchi's "secondary tetanus"). It became clear that bioelectric potentials are not random (side) phenomena in the activity of living tissues, but signals by which commands are transmitted in the body in the nervous system and from it to muscles and other organs, and thus living tissues interact with each other. using "electric tongue".
It was possible to understand this "language" much later, after the invention of physical devices that capture bioelectric potentials. One of the first such devices was a simple telephone. The remarkable Russian physiologist N.E. Vvedensky, using a telephone, discovered a number of important physiological properties nerves and muscles. Using the phone, it was possible to listen to bioelectric potentials, i.e. explore them by observation. A significant step forward was the invention of a technique for objective graphic recording of bioelectric phenomena. The Dutch physiologist Einthoven invented a string galvanometer - a device that made it possible to register on photo paper the electrical potentials arising from the activity of the heart - an electrocardiogram (ECG). In our country, the pioneer of this method was A.F. Samoilov, a prominent physiologist, a student of I.M. Sechenov and I.P. Pavlov, who worked for some time in Einthoven’s laboratory in Leiden.
History has preserved curious documents. A.F. Samoilov wrote a joking letter in 1928:
“Dear Einthoven, I am not writing a letter to you, but to your dear and respected string galvanometer. Therefore, I turn to him: Dear galvanometer, I have just learned about your anniversary.
25 years ago you drew the first electrocardiogram. Congratulations. I do not want to hide from you that I like you, despite the fact that you sometimes play pranks. I'm amazed at how much you've accomplished in 25 years. If we could count the number of meters and kilometers of photographic paper used for recording by your strings in all parts of the world, the resulting figures would be enormous. You have created a new industry. You also have philological merits;
Very soon the author received an answer from Einthoven, who wrote: “I have fulfilled your request exactly and read the letter to the galvanometer. Undoubtedly, he listened and accepted with pleasure and joy everything that you wrote. He did not suspect that he had done so much for humanity. But at the place where you say that he cannot read, he suddenly became furious ... so that my family and I even got excited. He shouted: What, I can't read? This is a terrible lie. Am I not reading all the secrets of the heart?” Indeed, electrocardiography from physiological laboratories very soon passed into the clinic as a very perfect method for studying the state of the heart, and many millions of patients today owe their lives to this method.
Samoilov A.F. Selected articles and speeches.-M.-L.: Publishing House of the Academy of Sciences of the USSR, 1946, p. 153.
Subsequently, the use of electronic amplifiers made it possible to create compact electrocardiographs, and telemetry methods make it possible to record ECG from astronauts in orbit, from athletes on the track, and from patients in remote areas, from where the ECG is transmitted via telephone wires to large cardiological institutions for a comprehensive analysis.
Objective graphic registration of bioelectric potentials served as the basis for the most important section of our science - electrophysiology. A major step forward was the proposal of the English physiologist Adrian to use electronic amplifiers to record bioelectrical phenomena. The Soviet scientist V.V. Pravdich Neminsky for the first time registered the biocurrents of the brain - he received an electroencephalogram (EEG). This method was later perfected by the German scientist Berger. At present, electroencephalography is widely used in the clinic, as is the graphic recording of the electrical potentials of muscles (electromyography), nerves, and other excitable tissues and organs. This made it possible to conduct a fine assessment of the functional state of these organs and systems. For physiology itself, these methods were also of great importance: they made it possible to decipher the functional and structural mechanisms of the activity of the nervous system and other organs and tissues, and the mechanisms of regulation of physiological processes.
An important milestone in the development of electrophysiology was the invention of microelectrodes, i.e. the thinnest electrodes, the tip diameter of which is equal to fractions of a micron. These electrodes can be introduced directly into the cell with the help of appropriate devices - micromanipulators and the bioelectric potentials can be recorded intracellularly.
Microelectrodes made it possible to decipher the mechanisms of biopotential generation, i.e. processes in cell membranes. Membranes are the most important formations, since through them the processes of interaction of cells in the body and individual elements of the cell with each other are carried out. The science of the functions of biological membranes—membranology—has become an important branch of physiology.
Methods of electrical stimulation of organs and tissues. An important milestone in the development of physiology was the introduction of the method of electrical stimulation of organs and tissues.
Living organs and tissues are able to respond to any influences: thermal, mechanical, chemical, etc., electrical stimulation by its nature is closest to the “natural language” by which living systems exchange information. The founder of this method was the German physiologist Dubois-Reymond, who proposed his famous "sled apparatus" (induction coil) for dosed electrical stimulation of living tissues.
Currently, electronic stimulators are used for this, which make it possible to receive electrical impulses of any shape, frequency and strength. Electrical stimulation has become an important method for studying the functions of organs and tissues. This method is widely used in the clinic. Designs of various electronic stimulators have been developed that can be implanted into the body. Electrical stimulation of the heart has become a reliable way to restore the normal rhythm and functions of this vital organ and has returned hundreds of thousands of people to work. Electrical stimulation of skeletal muscles is being successfully applied, and methods of electrical stimulation of parts of the brain using implanted electrodes are being developed. The latter, with the help of special stereotaxic devices, are injected into strictly defined nerve centers (with an accuracy of fractions of a millimeter). This method, transferred from physiology to the clinic, made it possible to cure thousands of severe neurologically ill patients and to obtain a large amount of important data on the mechanisms of work. human brain(N. P. Bekhtereva). We have talked about this not only to give an idea of some of the methods of physiological research, but also to illustrate the importance of physiology for the clinic.
In addition to recording electrical potentials, temperature, pressure, mechanical movements, and other physical processes, as well as the results of the impact of these processes on the body, chemical methods are widely used in physiology.
Chemical methods in physiology. The language of electrical signals is not the most universal in the body. The most common is the chemical interaction of life processes (chains of chemical processes occurring in living tissues). Therefore, a field of chemistry has arisen that studies these processes - physiological chemistry. Today it has become an independent science - biological chemistry, the data of which reveal the molecular mechanisms of physiological processes. The physiologist makes extensive use of chemical methods in his experiments, as well as methods that have arisen at the intersection of chemistry, physics, and biology. These methods have already given rise to new branches of science, for example, biophysics, which studies the physical side of physiological phenomena.
The physiologist widely uses the method of labeled atoms. In modern physiological research, other methods borrowed from the exact sciences are also used. They provide truly invaluable information in the analysis of various mechanisms of physiological processes.
Electrical recording of non-electric quantities. Significant progress in physiology today is associated with the use of electronic technology. Sensors are used - converters of various non-electrical phenomena and quantities (motion, pressure, temperature, concentration of various substances, ions, etc.) into electrical potentials, which are then amplified by electronic amplifiers and recorded by oscilloscopes. A huge number of different types of such recording devices have been developed that make it possible to record many physiological processes on an oscilloscope. A number of devices use additional effects on the body (ultrasonic or electromagnetic waves, high-frequency electrical vibrations, etc.). In such cases, the change in the magnitude of the parameters of these effects, which change certain physiological functions, is recorded. The advantage of such devices is that the transducer-sensor can be mounted not on the organ under study, but on the surface of the body. Waves, oscillations, etc. affecting the body. penetrate into the body and after exposure to the investigated function or organ are recorded by the sensor. This principle is used, for example, for ultrasonic flow meters that determine the velocity of blood flow in vessels, rheographs and rheopletismographs that record changes in the amount of blood filling in various parts of the body, and many other devices. Their advantage is the ability to study the body at any time without preliminary operations. In addition, such studies do not harm the body. Most modern methods of physiological research in the clinic are based on these principles. In the USSR, the initiator of the use of radioelectronic technology for physiological research was Academician VV Parin.
A significant advantage of such recording methods is that the physiological process is converted by the sensor into electrical oscillations, and the latter can be amplified and transmitted by wire or radio to any distance from the object under study. This is how telemetry methods arose, with the help of which it is possible to register physiological processes in the body of an astronaut in orbit, a pilot in flight, an athlete on a track, a worker during labor activity, etc. in a ground laboratory. The registration itself does not in any way interfere with the activities of the subjects.
However, the deeper the analysis of processes, the more the need for synthesis arises, i.e. creating a whole picture of phenomena from individual elements.
The task of physiology is that, along with the deepening of analysis, it is also necessary to carry out a synthesis continuously, to give a holistic view of the organism as a system.
The laws of physiology make it possible to understand the reaction of the body (as an integral system) and all its subsystems under certain conditions, under certain influences, etc.
Therefore, any method of influencing the body, before entering clinical practice, undergoes a comprehensive test in physiological experiments.
Method of acute experiment. The progress of science is connected not only with the development of experimental techniques and research methods. It also depends to a large extent on the evolution of the thinking of physiologists, on the development of methodological and methodological approaches to the study of physiological phenomena. From the beginning of its inception until the 80s of the last century, physiology remained an analytical science. She divided the body into separate organs and systems and studied their activity in isolation. The main methodological technique of analytical physiology was experiments on isolated organs, or so-called acute experiments. At the same time, in order to gain access to any internal organ or system, the physiologist had to engage in vivisection (live cutting).
The animal was tied to a machine and a complex and painful operation was performed.
This was hard work, but science did not know any other way to penetrate into the depths of the body.
It was not only the moral side of the problem. Severe tortures, unbearable sufferings to which the organism was subjected, grossly disrupted the normal course of physiological phenomena and did not allow understanding the essence of the processes occurring in natural conditions, in the norm. Significantly did not help and the use of anesthesia, as well as other methods of anesthesia. Animal fixation, impact narcotic substances, surgery, blood loss - all this completely changed and disrupted the normal course of life activity. A vicious circle formed. In order to investigate this or that process or function of an internal organ or system, it was necessary to penetrate into the depths of the organism, and the very attempt of such penetration disrupted the course of life processes, for the study of which the experiment was undertaken. In addition, the study of isolated organs did not give an idea of their true function in the conditions of a holistic, undamaged organism.
Method of chronic experiment. The greatest merit of Russian science in the history of physiology was that one of its most talented and brightest representatives I.P.
Pavlov managed to find a way out of this impasse. IP Pavlov was very painfully aware of the shortcomings of analytical physiology and acute experiment. He found a way to look into the depths of the body without violating its integrity. This was the method of a chronic experiment carried out on the basis of "physiological surgery".
On an anesthetized animal, under conditions of sterility and observance of the rules of surgical technique, a complex operation was previously performed, which allowed access to one or another internal organ, a “window” was made into a hollow organ, a fistula tube was implanted or a gland duct was brought out and sutured to the skin. The experiment itself began many days later, when the wound healed, the animal recovered and, in terms of the nature of the course of physiological processes, practically did not differ from a normal healthy one. Thanks to the imposed fistula, it was possible to study for a long time the course of certain physiological processes in the natural conditions of behavior.
PHYSIOLOGY OF A WHOLE ORGANISM It is well known that science develops depending on the success of methods.
The Pavlovian method of chronic experiment created a fundamentally new science - the physiology of the whole organism, synthetic physiology, which was able to reveal the influence of the external environment on physiological processes, to detect changes in the functions of various organs and systems to ensure the life of the organism in various conditions.
With the advent of modern technical means for studying life processes, it has become possible to study the functions of many internal organs, not only in animals, but also in humans, without preliminary surgical operations. "Physiological surgery" as a methodological technique in a number of branches of physiology has been supplanted by modern methods of bloodless experiment. But the point is not in this or that specific technique, but in the methodology of physiological thinking. I. P. Pavlov created a new methodology, and physiology developed as synthetic science and a systematic approach has organically become inherent in it.
An integral organism is inextricably linked with its external environment, and therefore, as I.M. Sechenov wrote, the scientific definition of an organism should also include the environment that influences it. The physiology of the whole organism studies not only the internal mechanisms of self-regulation of physiological processes, but also the mechanisms that ensure continuous interaction and inseparable unity of the organism with the environment.
The regulation of vital processes, as well as the interaction of the organism with the environment, is carried out on the basis of principles common to regulation processes in machines and automated production. These principles and laws are studied by a special field of science - cybernetics.
Physiology and Cybernetics IP PAVLOV (1849-1936) Cybernetics (from the Greek kybernetike - the art of control) is the science of controlling automated processes. Control processes, as you know, are carried out by signals that carry certain information. In the body, such signals are nerve impulses of an electrical nature, as well as various chemicals.
Cybernetics studies the processes of perception, coding, processing, storage and reproduction of information. In the body for these purposes, there are special devices and systems (receptors, nerve fibers, nerve cells, etc.).
Technical cybernetic devices have made it possible to create models that reproduce some of the functions of the nervous system. However, the functioning of the brain as a whole is not yet amenable to such modeling, and further research is needed.
The union of cybernetics and physiology arose only three decades ago, but during this time the mathematical and technical arsenal of modern cybernetics has ensured significant progress in the study and modeling of physiological processes.
Mathematics and computer technology in physiology. Simultaneous (synchronous) recording of physiological processes makes it possible to perform their quantitative analysis and study the interaction between various phenomena. This requires precise mathematical methods, the use of which also marked a new important step in the development of physiology. Mathematization of investigations makes it possible to use electronic computers in physiology. This not only increases the speed of information processing, but also makes it possible to perform such processing directly at the time of the experiment, which makes it possible to change its course and the tasks of the study itself in accordance with the results obtained.
Thus, as it were, a turn of the spiral in the development of physiology was completed. At the dawn of the emergence of this science, research, analysis and evaluation of the results were carried out by the experimenter simultaneously in the process of observation, directly during the experiment itself. Graphical recording made it possible to separate these processes in time and to process and analyze the results after the end of the experiment.
Radio electronics and cybernetics have made it possible to combine analysis and processing of results with the conduct of the experiment itself, but on a fundamentally different basis: the interaction of many different physiological processes is simultaneously studied and the results of such interaction are analyzed quantitatively. This made it possible to carry out the so-called controlled automatic experiment, in which a computer helps the researcher not only to analyze the results, but also to change the course of the experiment and the formulation of problems, as well as the types of influence on the organism, depending on the nature of the organism's reactions arising directly in the course of experience. Physics, mathematics, cybernetics and others exact sciences re-equipped physiology and provided the doctor with a powerful arsenal of modern technical means for an accurate assessment of the functional state of the body and for influencing the body.
Mathematical modeling in physiology. Knowledge of physiological regularities and quantitative relationships between various physiological processes made it possible to create their mathematical models. With the help of such models, these processes are reproduced on electronic computers, exploring various variants of reactions, i.e. their possible future changes under certain influences on the body (drugs, physical factors or extreme environmental conditions). Even now, the union of physiology and cybernetics has proved to be useful in carrying out severe surgical operations and in other emergency conditions that require an accurate assessment of both the current state of the most important physiological processes of the body and the prediction of possible changes. This approach makes it possible to significantly increase the reliability of the "human factor" in difficult and responsible parts of modern production.
Physiology of the XX century. has significant success not only in the field of revealing the mechanisms of life processes and control of these processes. She made a breakthrough into the most complex and mysterious area - into the area of mental phenomena.
The physiological basis of the psyche - the higher nervous activity of man and animals has become one of the important objects of physiological research.
OBJECTIVE STUDY OF THE HIGHER NERVOUS ACTIVITY For thousands of years it has been generally accepted that human behavior is determined by the influence of some non-material entity (“soul”), which the physiologist cannot cognize.
I. M. Sechenov was the first of the physiologists of the world who dared to present behavior on the basis of the reflex principle, i.e. on the basis of the mechanisms of nervous activity known in physiology. In his famous book "Reflexes of the Brain", he showed that no matter how complex the external manifestations of human mental activity may seem to us, sooner or later they come down to only one thing - muscle movement.
“Does a child smile at the sight of a new toy, does Garibaldi laugh when he is persecuted for excessive love for his homeland, does Newton invent world laws and writes them on paper, does a girl tremble at the thought of a first date, the end result of the thought is always one thing - muscular movement,” wrote I. M. Sechenov.
Analyzing the formation of a child's thinking, I. M. Sechenov showed step by step that this thinking is formed as a result of the influences of the external environment, combined with each other in various combinations, causing the formation of various associations.
Our thinking (spiritual life) is naturally formed under the influence of environmental conditions, and the brain is an organ that accumulates and reflects these influences. No matter how complex the manifestations of our mental life may seem to us, our internal psychological make-up is a natural result of the conditions of upbringing, the influence of the environment. At 999/1000, the mental content of a person depends on the conditions of upbringing, the influences of the environment in the broad sense of the word, - wrote I. M. Sechenov, - and only at 1/1000 it is determined by innate factors. Thus, for the first time, the principle of determinism, the basic principle of the materialistic worldview, was extended to the most complex area of life phenomena, to the processes of man's spiritual life. IM Sechenov wrote that one day a physiologist will learn to analyze the external manifestations of brain activity just as accurately as a physicist can analyze a musical chord. I. M. Sechenov's book was a work of genius, asserting materialistic positions in the most complex spheres of man's spiritual life.
Sechenov's attempt to substantiate the mechanisms of brain activity was a purely theoretical attempt. The next step was needed - experimental studies of the physiological mechanisms underlying mental activity and behavioral reactions. And this step was taken by IP Pavlov.
The fact that it was I. P. Pavlov, and no one else, who became the heir to the ideas of I. M. Sechenov and was the first to penetrate into the basic secrets of the work of the higher parts of the brain, is not accidental. The logic of his experimental physiological studies led to this. Studying the processes of vital activity in the body in the conditions of the natural behavior of the animal, I.
P. Pavlov drew attention to the important role of mental factors influencing all physiological processes. The observation of I. P. Pavlov did not escape the fact that saliva, I. M. SECHENOV (1829-1905), gastric juice and other digestive juices begin to be secreted in the animal not only at the time of eating, but long before eating, at the sight of food , the sound of footsteps of the attendant who usually feeds the animal. IP Pavlov drew attention to the fact that appetite, a passionate desire for food, is as powerful a juice-releasing agent as food itself. Appetite, desire, mood, experiences, feelings - all these were mental phenomena. Before I.P. Pavlov, they were not studied by physiologists. IP Pavlov, on the other hand, saw that the physiologist has no right to ignore these phenomena, since they powerfully interfere with the course of physiological processes, changing their character. Therefore, the physiologist was obliged to study them. But how? Before I.P. Pavlov, these phenomena were considered by a science called zoopsychology.
Turning to this science, IP Pavlov had to move away from the solid ground of physiological facts and enter the realm of fruitless and groundless fortune-telling about the apparent mental state of animals. To explain human behavior, the methods used in psychology are legitimate, because a person can always report his feelings, moods, experiences, etc. Animal psychologists blindly transferred to animals the data obtained during the examination of a person, and also spoke of "feelings", "moods", "experiences", "desires", etc. in an animal, without being able to check whether this is so or not. For the first time in the Pavlovian laboratories, there were as many opinions about the mechanisms of the same facts as there were observers who saw these facts. Each of them interpreted them in his own way, and it was not possible to check the correctness of any of the interpretations. IP Pavlov realized that such interpretations are meaningless and therefore took a decisive, truly revolutionary step. Without trying to guess about certain internal mental states of the animal, he began to study the behavior of the animal objectively, comparing certain effects on the body with the body's responses. This objective method made it possible to reveal the laws underlying the behavioral reactions of the organism.
The method of objective study of behavioral reactions has created a new science - the physiology of higher nervous activity with its precise knowledge of the processes occurring in the nervous system under various environmental influences. This science has given a lot for understanding the essence of the mechanisms of human mental activity.
The physiology of higher nervous activity created by IP Pavlov became the natural scientific basis of psychology. It became the natural-scientific basis of Lenin's theory of reflection, is of great importance in philosophy, medicine, pedagogy and in all those sciences that in one way or another face the need to study the inner (spiritual) world of man.
The value of the physiology of higher nervous activity for medicine. The teachings of I.P.
Pavlov's theory of higher nervous activity is of great practical importance. It is known that the patient is cured not only by drugs, a scalpel or a procedure, but also by the word of the doctor, trust in him, a passionate desire to recover. All these facts were known to Hippocrates and Avicenna. However, for thousands of years they were perceived as evidence of the existence of a powerful, “God-given soul”, subjugating a “mortal body”. The teachings of I. P. Pavlov tore the veil of mystery from these facts.
It became clear that the seemingly magical effect of talismans, a sorcerer or shaman's spells is nothing more than an example of the influence of higher parts of the brain on internal organs and the regulation of all life processes. The nature of this influence is determined by the impact on the body of environmental conditions, the most important of which for a person are social conditions - in particular, the exchange of thoughts in human society with the help of a word. IP Pavlov showed for the first time in the history of science that the power of a word lies in the fact that words and speech are a special system of signals inherent only in man, which naturally changes behavior and mental status. Pavlovian teaching expelled idealism from the last, it would seem, impregnable refuge - the idea of a "soul" given by God. It put a powerful weapon in the hands of the doctor, giving him the opportunity to use the word correctly, showing the most important role of moral influence on the patient for the success of treatment.
CONCLUSION IP Pavlov can rightfully be considered the founder of modern physiology of the integral organism. Other outstanding Soviet physiologists also made a major contribution to its development. A. A. Ukhtomsky created the doctrine of the dominant as the main principle of the activity of the central nervous system (CNS). L. A. Orbeli founded the Evolion He owns the fundamental work on the adaptive trophic function of the sympathetic nervous system. K. M. Bykov revealed the presence of conditioned reflex regulation of the functions of internal organs, showing that vegetative functions are not autonomous, that they are subject to the influences of the higher parts of the central nervous system and can change under the influence of conditioned signals. For a person, the most important conditional signal is the word. This signal is capable of changing the activity of internal organs, which is of great importance for medicine (psychotherapy, deontology, etc.).
L. S. STERN I. S. BERITASHVILI (1878-1968) (1885-1974) P. K. Anokhin developed the theory of the functional system - universal scheme regulation of physiological processes and behavioral reactions of the body.
The outstanding neurophysiologist I. S. Beritov (Beritashvili) created a number of original trends in the physiology of the neuromuscular and central nervous systems. L. S. Stern is the author of the doctrine of the hematoencephalological barrier and histohematogenous barriers - regulators of the immediate internal environment of organs and tissues. VV Parin owns major discoveries in the field of regulation of the cardiovascular system (Larin's reflex). He is the founder of space physiology and the initiator of the introduction of methods of radio electronics, cybernetics, and mathematics into physiological research. E. A. Asratyan created the doctrine of the mechanisms of compensation for impaired functions. He is the author of a number of fundamental works that develop the main provisions of the teachings of IP Pavlov. VN Chernigovsky developed the theory of interoreceptors.
Soviet physiologists have priority in PARIN (1903-1971) in the creation of an artificial heart (A. A. Bryukhonenko), EEG recording (V. V. Pravdich-Neminsky), the creation of such important and new areas in science as space physiology, labor physiology, physiology of sports, the study of the physiological mechanisms of adaptation, regulation and internal mechanisms for the implementation of many physiological functions. These and many other studies are of paramount importance for medicine.
Knowledge of the vital processes that take place in various organs and tissues, the mechanisms of regulation of vital phenomena, understanding the essence of the physiological functions of the body and the processes that interact with the environment are the fundamental theoretical basis on which the training of the future doctor is based.
Section I GENERAL PHYSIOLOGY INTRODUCTION Each of the hundred trillion cells of the human body is characterized by an extremely complex structure, the ability to self-organize and interact with other cells in many ways. The number of processes carried out by each cell, and the amount of information processed in this process, far exceeds what takes place today in any large industrial complex. Nevertheless, the cell is only one of the relatively elementary subsystems in a complex hierarchy of systems that form a living organism.
All of these systems are the highest degree orderly. The normal functional structure of any of them and the normal existence of each element of the system (including each cell) are possible due to the continuous exchange of information between elements (and between cells).
The exchange of information occurs through direct (contact) interaction between cells, as a result of the transport of substances with tissue fluid, lymph and blood (humoral communication - from Latin humor - liquid), as well as during the transfer of bioelectric potentials from cell to cell, which is the most fast way transmission of information in the body. At multicellular organisms a special system has been developed that ensures the perception, transmission, storage, processing and reproduction of information encoded in electrical signals. This is the nervous system that has reached the highest development in man. In order to understand the nature of bioelectric phenomena, i.e., the signals by which the nervous system transmits information, it is necessary first of all to consider some aspects general physiology so-called excitable tissues, which include nervous, muscular and glandular tissues.
Chapter PHYSIOLOGY OF EXCITABLE TISSUES All living cells have irritability, that is, the ability, under the influence of certain factors of the external or internal environment, the so-called stimuli, to pass from a state of physiological rest to a state of activity. However, the term "excitable cells" is used only in relation to nerve, muscle and secretory cells that are capable of generating specialized forms of electrical potential oscillations in response to the action of a stimulus.
The first data on the existence of bioelectric phenomena (“animal electricity”) were obtained in the third quarter of the 18th century. at. the study of the nature of the electrical discharge applied by some fish in defense and attack. A long-term scientific dispute (1791-1797) between the physiologist L. Galvani and the physicist A. Volta about the nature of "animal electricity" ended with two major discoveries: facts were established indicating the presence of electrical potentials in the nervous and muscle tissues, and a new method was discovered. receiving electric current with the help of dissimilar metals - a galvanic cell ("voltaic column") was created. However, the first direct measurements of potentials in living tissues became possible only after the invention of galvanometers. A systematic study of potentials in muscles and nerves at rest and in a state of excitation was begun by Dubois-Reymond (1848). Further advances in the study of bioelectrical phenomena were closely connected with the improvement of the technique for recording fast fluctuations in the electric potential (string, loop, and cathode oscilloscopes) and methods for their removal from single excitable cells. A qualitatively new stage in the study of electrical phenomena in living tissues - 40-50s of our century. Using intracellular microelectrodes, it was possible to directly record the electrical potentials of cell membranes. Advances in electronics have made it possible to develop methods for studying ionic currents flowing through a membrane under changes in the membrane potential or under the action of biologically active compounds on membrane receptors. IN last years a method has been developed that makes it possible to register ion currents flowing through single ion channels.
There are the following main types of electrical responses of excitable cells:
local response;
propagating action potential and trace potentials accompanying it;
excitatory and inhibitory postsynaptic potentials;
generator potentials, etc. All these potential fluctuations are based on reversible changes in the permeability of the cell membrane for certain ions. In turn, the change in permeability is a consequence of the opening and closing of ion channels existing in the cell membrane under the influence of the acting stimulus.
The energy used to generate electric potentials is stored in the resting cell in the form of concentration gradients of Na+, Ca2+, K+, C1~ ions on both sides of the surface membrane. These gradients are created and maintained by specialized molecular devices, the so-called membrane ion pumps. The latter use for their work the metabolic energy released during the enzymatic cleavage of the universal cellular energy donor - adenosine triphosphoric acid (ATP).
The study of electrical potentials accompanying the processes of excitation and inhibition in living tissues is important both for understanding the nature of these processes and for revealing the nature of disturbances in the activity of excitable cells in various types of pathology.
Methods for recording the electrical potentials of the heart (electrocardiography), brain (electroencephalography), and muscles (electromyography) are especially widespread in modern clinics.
REST POTENTIAL The term "membrane potential" (rest potential) is commonly referred to as the trans membrane potential difference;
existing between the cytoplasm and the external solution surrounding the cell. When a cell (fiber) is in a state of physiological rest, its internal potential is negative in relation to the external one, conventionally taken as zero. In different cells, the membrane potential varies from -50 to -90 mV.
To measure the resting potential and trace its changes caused by one or another effect on the cell, the technique of intracellular microelectrodes is used (Fig. 1).
The microelectrode is a micropipette, i.e., a thin capillary drawn from a glass tube. The diameter of its tip is about 0.5 µm. The micro-pisette is filled saline solution(usually 3 M K.S1), a metal electrode (chlorinated silver wire) is immersed in it and connected to an electrical measuring instrument - an oscilloscope equipped with a DC amplifier.
The microelectrode is installed over the object under study, for example, a skeletal muscle, and then, using a micromanipulator - a device equipped with micrometric screws, is introduced into the cell. An electrode of normal size is immersed in a normal saline solution containing the tissue to be examined.
As soon as the microelectrode pierces the surface membrane of the cell, the oscilloscope beam immediately deviates from its initial (zero) position, thereby revealing the existence of a potential difference between the surface and the contents of the cell. Further advancement of the microelectrode inside the protoplasm does not affect the position of the oscilloscope beam. This indicates that the potential is indeed localized on the cell membrane.
Upon successful introduction of the microelectrode, the membrane tightly covers its tip, and the cell retains the ability to function for several hours without showing signs of damage.
There are many factors that change the resting potential of cells: the application of an electric current, a change in the ionic composition of the medium, the action of certain toxins, a violation of the oxygen supply to the tissue, etc. In all those cases when the internal potential decreases (becomes less negative), talk about depolarization of the membrane;
the opposite potential shift (an increase in the negative charge of the inner surface of the cell membrane) is called hyperpolarization.
THE NATURE OF THE REST POTENTIAL Back in 1896, V. Yu. Chagovets put forward a hypothesis about the ionic mechanism of electrical potentials in living cells and made an attempt to apply the Arrhenius theory of electrolytic dissociation to explain them. In 1902, Yu. Bernstein developed the membrane-ion theory, which was modified and experimentally substantiated by Hodgkin, Huxley and Katz (1949-1952). The latter theory is now generally accepted. According to this theory, the presence of electrical potentials in living cells is due to the inequality in the concentration of Na+, K+, Ca2+ and C1~ ions inside and outside the cell and the different permeability of the surface membrane for them.
From the data in Table. Figure 1 shows that the content of the nerve fiber is rich in K+ and organic anions (practically not penetrating through the membrane) and poor in Na+ and C1~.
The concentration of K + in the cytoplasm of nerve and muscle cells is 40-50 times higher than in the external solution, and if the membrane at rest was permeable only for these ions, then the resting potential would correspond to the equilibrium potassium potential (Ek), calculated by the Nernst formula :
where R is the gas constant, F is the Faraday number, T is the absolute temperature, Ko is the concentration of free potassium ions in the external solution, Ki is their concentration in the cytoplasm To understand how this potential arises, consider the following model experiment (Fig. 2).
Let us imagine a vessel separated by an artificial semipermeable membrane. The walls of the pores of this membrane are electronegatively charged; therefore, they allow only cations to pass through and are impermeable to anions. In both halves of the vessel per liter of saline containing K + ions, however, their concentration in the right side of the vessel is higher than in the left. Due to this concentration gradient, K+ ions begin to diffuse from the right half of the vessel to the left, bringing their positive charge there. This leads to the fact that nonpenetrating anions begin to accumulate near the membrane in the right half of the vessel. With their negative charge, they will electrostatically hold K+ at the membrane surface in the left half of the vessel. As a result, the membrane is polarized, and a potential difference is created between its two surfaces, which corresponds to the equilibrium potassium potential (k).
The assumption that at rest the membrane of nerve and muscle fibers is selectively permeable to K+ and that it is their diffusion that creates the resting potential was made by Bernstein as early as 1902 and confirmed by Hodgkin et al. in 1962 in experiments on isolated giant squid axons. From a fiber with a diameter of about 1 mm, the cytoplasm (axoplasm) was carefully squeezed out, and the collapsed membrane was filled with an artificial saline solution. When the concentration of K+ in the solution was close to intracellular, a potential difference was established between the inner and outer sides of the membrane, close to the value of the normal resting potential (-50-=---80 mV), and the fiber conducted impulses. With a decrease in the intracellular and an increase in the external concentration of K.+, the membrane potential decreased or even its sign changed (the potential became positive if the K+ concentration in the external solution was higher than in the internal one).
Such experiments have shown that the concentrated K+ gradient is indeed the main factor determining the magnitude of the resting potential of the nerve fiber. However, the quiescent membrane is permeable not only to K+, but (though to a much lesser extent) also to Na+. Diffusion of these positively charged ions into the cell reduces absolute value the internal negative potential of the cell created by K+ diffusion. Therefore, the resting potential of the fibers (-50 - 70 mV) is less negative than the potassium equilibrium potential calculated using the Nernst formula.
Ions C1 ~ in nerve fibers do not play a significant role in the genesis of the resting potential, since the permeability of the resting membrane for them is relatively small. In contrast to this, in skeletal muscle fibers, the permeability of the resting membrane for chloride ions is comparable to that of potassium, and therefore diffusion of C1~ into the cell increases the value of the resting potential. Calculated chlorine equilibrium potential (Ecl) at the ratio Thus, the value of the resting potential of the cell is determined by two main factors: a) the ratio of the concentrations of cations and anions penetrating through the resting surface membrane;
b) the ratio of the permeability of the membrane for these ions.
For a quantitative description of this regularity, the Goldmann-Hodgkin-Katz equation is usually used:
where Em is the resting potential, Pk, PNa, Pcl are the permeability of the membrane for K+, Na+ and C1~ ions, respectively;
Cl0- - external concentrations of K+, Na+ and Сl- ions, and Ki+ Nai+ and Cli- - their internal concentrations.
It was calculated that in an isolated giant squid axon at Em = -50 mV, there is the following relationship between the ion permeability of the resting membrane:
Рк:РNa:РCl = 1:0.04:0.45.
The equation provides an explanation for many changes in the resting potential of the cell observed in the experiment and in natural conditions, for example, its persistent depolarization under the action of certain toxins that cause an increase in the sodium permeability of the membrane. These toxins include plant poisons: veratridine, aconitine, and one of the most powerful neurotoxins, batra chotoxin, produced by the skin glands of Colombian frogs.
Membrane depolarization, as follows from the equation, can also occur with unchanged PNA if the external concentration of K+ ions is increased (i.e., the ratio Ko/Ki is increased). Such a change in the resting potential is by no means only a laboratory phenomenon. The fact is that the concentration of K + in the intercellular fluid increases markedly during the activation of nerve and muscle cells, accompanied by an increase in PK. The concentration of K+ in the intercellular fluid increases especially significantly in case of impaired blood supply (ischemia) to tissues, for example, myocardial ischemia. The resulting depolarization of the membrane leads to the termination of the generation of action potentials, i.e., disruption of the normal electrical activity of the cells.
THE ROLE OF METABOLISM IN THE GENESIS AND MAINTENANCE OF THE RESTING POTENTIAL (MEMBRANE SODIUM PUMP) Despite the fact that the fluxes of Na+ and K+ through the membrane at rest are small, the difference between the concentrations of these ions inside and outside the cell should eventually equalize if there would be no special molecular device in the cell membrane - the “sodium pump”, which ensures the removal (“pumping out”) of Na + penetrating into it from the cytoplasm and the introduction (“injection”) of K + into the cytoplasm. The sodium pump moves Na + and K + against their concentration gradients, that is, it does a certain amount of work. The direct source of energy for this work is an energy-rich (macroergic) compound - adenosine triphosphoric acid (ATP), which is a universal source of energy for living cells. The splitting of ATP is carried out by protein macromolecules - the enzyme adenosine triphosphatase (ATPase), localized in the surface membrane of the cell. The energy released during the splitting of one ATP molecules, ensures the removal of three Na + ions from the cell in exchange for two K + ions entering the cell from the outside.
The inhibition of ATP-ase activity, caused by some chemical compounds (for example, the cardiac glycoside ouabain), disrupts the pump, as a result of which the cell loses K + and is enriched with Na +. The inhibition of oxidative and glycolytic processes in the cell, which ensure the synthesis of ATP, leads to the same result. In the experiment, this is achieved with the help of poisons that inhibit these processes. Under conditions of disruption of the blood supply to tissues, weakening of the process of tissue respiration, the work of the electrogenic pump is inhibited and, as a result, the accumulation of K + in the intercellular gaps and depolarization of the membrane.
The role of ATP in the mechanism of active Na+ transport has been directly proven in experiments on giant squid nerve fibers. It was found that by injecting ATP into the fiber, one can temporarily restore the functioning of the sodium pump, which was disturbed by the inhibitor of respiratory enzymes, cyanide.
Initially, it was believed that the sodium pump is electrically neutral, i.e., the number of exchanged Na+ and K+ ions is equal. Later it turned out that for every three Na + ions removed from the cell, only two K + ions enter the cell. This means that the pump is electrogenic: it creates a potential difference across the membrane, which is added to the resting potential.
This contribution of the sodium pump to the normal value of the resting potential in different cells is not the same: it is apparently insignificant in the nerve fibers of the squid, but significant for the resting potential (about 25% of the total value) in giant mollusk neurons, smooth muscles.
Thus, in the formation of the resting potential, the sodium pump plays a dual role: 1) it creates and maintains a transmembrane gradient of Na+ and K+ concentrations;
2) generates a potential difference that sums up with the potential created by K+ diffusion along the concentration gradient.
ACTION POTENTIAL An action potential is a rapid fluctuation of the membrane potential that occurs when nerve, muscle, and some other cells are excited. It is based on changes in the ionic permeability of the membrane. The amplitude and nature of the temporary changes in the action potential depend little on the strength of the stimulus that causes it, it is only important that this strength is not less than a certain critical value, which is called the threshold of irritation. Having arisen at the site of irritation, the action potential propagates along the nerve or muscle fiber without changing its amplitude.
The presence of a threshold and the independence of the amplitude of the action potential from the strength of the stimulus that caused it are called the all-or-nothing law.
Under natural conditions, action potentials are generated in nerve fibers upon stimulation of receptors or excitation of nerve cells. The propagation of action potentials along nerve fibers ensures the transmission of information in the nervous system. Upon reaching the nerve endings, action potentials cause the secretion of chemicals (mediators) that ensure signal transmission to muscle or nerve cells. In muscle cells, action potentials initiate a chain of processes that cause a contractile act. Ions penetrating into the cytoplasm during the generation of action potentials have a regulatory effect on cell metabolism and, in particular, on the processes of protein synthesis constituting ion channels and ion pumps.
To register action potentials, extra- or intracellular electrodes are used. In extracellular recording, the electrodes are brought to the outer surface of the fiber (cell). This makes it possible to detect that the surface of the excited area for a very short time (in the nerve fiber for a thousandth of a second) becomes negatively charged with respect to the neighboring resting area.
The use of intracellular microelectrodes makes it possible to quantitatively characterize changes in the membrane potential during the ascending and descending phases of the action potential. It has been established that during the ascending phase (the phase of depolarization), not only the resting potential disappears (as was originally assumed), but a potential difference of the opposite sign occurs: the internal contents of the cell become positively charged with respect to the external environment, in other words, a reversion occurs. membrane potential. During the descending phase (repolarization phase), the membrane potential returns to its original value. On fig. Figures 3 and 4 show examples of recordings of action potentials in the frog skeletal muscle fiber and the squid giant axon. It can be seen that at the moment of reaching the apex (peak), the membrane potential is + 30 / + 40 mV and the peak oscillation is accompanied by long trace changes in the membrane potential, after which the membrane potential is set at the initial level. The duration of the action potential peak in various nerve and skeletal muscle fibers is variable Fig. 5. Summation of trace potentials in the phrenic nerve of a cat during its short-term stimulation by rhythmic impulses.
The ascending part of the action potential is not visible. Recordings begin with negative trace potentials (a), passing into positive potentials (b). The upper curve is the response to a single stimulus. With an increase in the frequency of stimulation (from 10 to 250 per 1 s), the trace positive potential (trace hyperpolarization) increases sharply.
It is from 0.5 to 3 ms, and the repolarization phase is longer than the depolarization phase.
The duration of the action potential, especially the repolarization phase, is closely dependent on temperature: when cooled by 10 ° C, the duration of the peak increases by about 3 times.
Changes in membrane potential following the peak of an action potential are called trace potentials.
There are two types of trace potentials - trace depolarization and trace hyperpolarization. The amplitude of trace potentials usually does not exceed a few millivolts (5-10% of the peak height), and their duration in different fibers ranges from several milliseconds to tens and hundreds of seconds.
The dependence of the action potential peak and trace depolarization can be considered using the electrical response of a skeletal muscle fiber as an example. From the entry in Fig. 3, it can be seen that the descending phase of the action potential (the repolarization phase) is divided into two unequal parts. At first, the potential drop occurs rapidly, and then it slows down strongly. This slow component of the descending phase of the action potential is called wake depolarization.
An example of trace hyperpolarization of the membrane accompanying the peak of the action potential in a single (isolated) giant squid nerve fiber is shown in Fig. 4. In this case, the descending phase of the action potential directly passes into the phase of trace hyperpolarization, the amplitude of which in this case reaches 15 mV. Trace hyperpolarization is characteristic of many non-fleshy nerve fibers of cold-blooded and warm-blooded animals. In myelinated nerve fibers, trace potentials are more complex. A trace depolarization can turn into a trace hyperpolarization, then sometimes a new depolarization occurs, only after that the resting potential is fully restored. Trace potentials, to a much greater extent than the peaks of action potentials, are sensitive to changes in the initial resting potential, the ionic composition of the medium, the oxygen supply to the fiber, etc.
A characteristic feature of trace potentials is their ability to change in the process of rhythmic impulsation (Fig. 5).
IONIC MECHANISM OF THE APPEARANCE OF THE ACTION POTENTIAL The action potential is based on changes in the ionic permeability of the cell membrane that develop sequentially over time.
As noted, at rest, the permeability of the membrane to potassium exceeds its permeability to sodium. As a result, the flow of K. + from the cytoplasm into the external solution exceeds the oppositely directed flow of Na +. Therefore, the outer side of the membrane at rest has a positive potential relative to the inner one.
Under the action of an irritant on the cell, the permeability of the membrane for Na + increases sharply and eventually becomes about 20 times greater than the permeability for K +. Therefore, the flow of Na+ from the external solution into the cytoplasm begins to exceed the outward potassium current. This leads to a change in the sign (reversion) of the membrane potential: the inner content of the cell becomes positively charged with respect to its outer surface. This change in membrane potential corresponds to the ascending phase of the action potential (depolarization phase).
The increase in membrane permeability to Na+ lasts only a very short time. Following this, the permeability of the membrane for Na + again decreases, and for K + increases.
The process leading to a decrease earlier Fig. 6. Time course of changes in sodium (g) Na increased sodium permeability and potassium (gk) permeability of the giant membrane membrane, called sodium inactivation. squid axon during sweat generation As a result of inactivation, the flow of Na + into the action cycle (V).
cytoplasm is sharply weakened. An increase in potassium permeability causes an increase in the flow of K + from the cytoplasm into the external solution. As a result of these two processes, membrane repolarization occurs: the inner contents of the cell again acquire a negative charge in relation to the outer solution. This potential change corresponds to the descending phase of the action potential (the repolarization phase).
One of the important arguments in favor of the sodium theory of the origin of action potentials was the close dependence of its amplitude on the concentration of Na+ in the external solution.
Experiments on giant nerve fibers perfused from the inside with saline solutions made it possible to obtain direct confirmation of the correctness of the sodium theory. It has been established that when the axoplasm is replaced with a saline solution rich in K+, the fiber membrane not only maintains the normal resting potential, but for a long time retains the ability to generate hundreds of thousands of action potentials of normal amplitude. If, on the other hand, K+ in the intracellular solution is partially replaced by Na+, and thereby the Na+ concentration gradient between the external environment and the internal solution is reduced, the amplitude of the action potential decreases sharply. With the complete replacement of K+ with Na+, the fiber loses its ability to generate action potentials.
These experiments leave no doubt that the surface membrane is indeed the place where the potential arises both at rest and during excitation. It becomes obvious that the difference between the concentrations of Na+ and K+ inside and outside the fiber is the source of the electromotive force that causes the emergence of the resting potential and the action potential.
On fig. 6 shows changes in sodium and potassium permeability of the membrane during action potential generation in the squid giant axon. Similar relationships take place in other nerve fibres, in the bodies of nerve cells, and also in the skeletal muscle fibers of vertebrates. Ca2+ ions play the leading role in the genesis of the ascending phase of the action potential in the skeletal muscles of crustaceans and smooth muscles of vertebrates. In myocardial cells, the initial rise in the action potential is associated with an increase in the membrane permeability for Na+, and the plateau of the action potential is due to an increase in the membrane permeability for Ca2+ ions as well.
ON THE NATURE OF THE IONIC PERMEABILITY OF THE MEMBRANE. ION CHANNELS The considered changes in the ion permeability of the membrane during action potential generation are based on the processes of opening and closing of specialized ion channels in the membrane, which have two important properties: 1) selectivity (selectivity) with respect to certain ions;
2) electrical excitability, i.e., the ability to open and close in response to changes in the membrane potential. The process of opening and closing the channel has a probabilistic character (membrane potential only determines the probability of the channel being in an open or closed state).
Like ion pumps, ion channels are formed by protein macromolecules penetrating the lipid bilayer of the membrane. The chemical structure of these macromolecules has not yet been deciphered; therefore, ideas about the functional organization of channels are still built mainly indirectly - on the basis of an analysis of data obtained from studies of electrical phenomena in membranes and the effect of various chemical agents (toxins, enzymes, drugs, etc.) etc.). It is generally accepted that the ion channel consists of the actual transport system and the so-called gate mechanism (“gate”) controlled by electric field membranes. The "gates" can be in two positions: they are completely closed or completely open, so the conductivity of a single open channel is a constant value.
The total conductivity of the membrane for a particular ion is determined by the number of simultaneously open channels permeable to a given ion.
This position can be written as follows:
where gi is the total permeability of the membrane for an intracellular ion;
N is the total number of corresponding ion channels (in a given region of the membrane);
a - share of open channels;
y is the conductivity of a single channel.
According to their selectivity, electrically excitable ion channels of nerve and muscle cells are subdivided into sodium, potassium, calcium, and chloride channels. This selectivity is not absolute:
the name of the channel indicates only the ion for which this channel is the most permeable.
Through open channels, ions move along concentration and electric gradients. These ion flows lead to changes in the membrane potential, which in turn changes the average number of open channels and, accordingly, the magnitude of ion currents, etc. potential. To study this dependence, the “potential fixation method” is used. Essence this method consists in forcibly maintaining the membrane potential at any given level. Thus, by applying a current to the membrane that is equal in magnitude, but opposite in sign to the ion current passing through open channels, and measuring this current at different potentials, researchers are able to trace the dependence of the potential on ionic conductivities. Time course of changes in sodium (gNa) and potassium (gK) membrane permeability upon depolarization of the axon membrane by 56 mV.
a - solid lines show permeability during prolonged depolarization, and dotted lines - during membrane repolarization after 0.6 and 6.3 ms;
b dependence of the peak value of sodium (gNa) and stationary level of potassium (gK) permeability on the membrane potential.
Rice. 8. Schematic representation of an electrically excitable sodium channel.
The channel (1) is formed by a protein macromolecule 2), the narrowed part of which corresponds to a "selective filter". The channel contains activation (m) and inactivation (h) gates, which are controlled by the electric field of the membrane. At the resting potential (a), the most probable is the “closed” position for the activation gate and the “open” position for the inactivation gates. Membrane depolarization (b) leads to a rapid opening of the t-gate and a slow closing of the h-gate; therefore, at the initial moment of depolarization, both pairs of gates are open and ions can move through the channel according to and with their concentration and electrical gradients. With continued depolarization, the inactivation “gate” closes and the channel goes into the inactivation state.
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Moscow "Medicine" 1985
For medical students
Human
Edited by
Corresponding Member USSR Academy of Medical Sciences G. I. KOSITS KO G "O
third edition,
revised and expanded
Approved by the Main Directorate of Educational Institutions of the Ministry of Health of the USSR as a textbook for students of medical institutes
>BK 28.903 F50
/DK 612(075.8) ■
[E, B. BABSKII], V. D. GLEBOVSKII, A. B. KOGAN, G. F. KOROTKO,
G. I. KOSITSKY, V; M Pokrovskii, Yu. V. Natchin, V. P. Skipetrov, B. I. Khodorov, A. I. Shapovalov, and I. A. Shevelev
Reviewer J..D.Boyenko, prof., head Department of Normal Physiology, Voronezh Medical Institute. N. N. Burdenko
UK1 5L4
1.1 "hi" Willi I
1 uedn u« i --c ; ■ ■■ ^ ■ *
human physiology/ Ed. G. I. Kositsky. - F50 3rd ed., Revised. and additional - M .: "Medicine", 1985. 544 e., ill.
In lane: 2 p. 20 k. 150,000 copies.
The third edition of the textbook (the second was published in 1972) was written in accordance with the achievements of modern science. New facts and concepts are presented, new chapters are included: "Peculiarities of higher nervous activity of a person", "Elements of labor physiology", mechanisms of training and adaptation", sections covering questions of biophysics and physiological cybernetics are expanded. Nine chapters of the textbook are drawn anew, the rest largely redesigned: .
The textbook corresponds to the program approved by the USSR Ministry of Health and is intended for students of medical institutes.
f^^00-241 BBK 28.903
039(01)-85
(6) Publishing house "Medicine", 1985
FOREWORD
12 years have passed since the previous edition of the textbook "Human Physiology" The responsible editor and one of the authors of the book, Academician of the Academy of Sciences of the Ukrainian SSR E.B. -
The team of authors of this publication includes well-known specialists in the relevant branches of physiology: Corresponding Member of the Academy of Sciences of the USSR, prof. A.I. Shapovalov" and Prof. Yu, V. Natochin (Heads of Laboratories of the I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry of the USSR Academy of Sciences), Prof. V.D. Glebovsky (Head of the Department of Physiology of the Leningrad Pediatric "Medical Institute) ; prof. , A.B. Kogan (Head of the Department of Human and Animal Physiology and Director of the Institute of Neurocybernetics of the Rostov State University), prof. G.F.Korotks (Head of the Department of Physiology of the Andijan Medical Institute), Ph.D. V.M. Pokrovsky (Head of the Department of Physiology of the Kuban Medical Institute), prof. B.I. Khodorov (head of the laboratory of the Institute of Surgery named after A.V. Vishnevsky of the USSR Academy of Medical Sciences), prof. I. A. Shevelev (Head of Laboratory, Institute of Higher Nervous Activity and Neurophysiology, USSR Academy of Sciences). -I
Over the past time, a large number of new facts, views, theories, discoveries and directions of our science have appeared. In this regard, 9 chapters in this edition had to be written anew, and the remaining 10 chapters were revised and supplemented. At the same time, to the extent possible, the authors tried to preserve the text of these chapters.
The new sequence of presentation of the material, as well as its combination into four main sections, is dictated by the desire to give the presentation logical harmony, consistency and, as far as possible, avoid duplication of material. ■ -
The content of the textbook corresponds to the program in physiology approved in 1981. Criticisms about the project and the program itself, expressed in the decision of the Bureau, Department of Physiology of the USSR Academy of Sciences (1980) and at the All-Union Conference of Heads of Departments of Physiology of Medical Universities (Suzdal, 1982), were also taken into account. In accordance with the program, chapters were introduced into the textbook that were not in the previous edition: “Peculiarities of higher nervous activity of a person” and “Elements of labor physiology, mechanisms of training and adaptation”, as well as expanded sections covering issues of private biophysics and physiological cybernetics. The authors took into account the fact that in 1983 a biophysics textbook for students of medical institutes was published (under the editorship of Prof. Yu A. Vladimirov) and that the elements of biophysics and cybernetics are set out in the textbook by Prof. A.N. Remizova "Medical and biological physics".
Due to the limited volume of the textbook, it was necessary, unfortunately, to omit the chapter "History of Physiology", as well as digressions into history in separate chapters. Chapter 1 gives only sketches of the formation and development of the main stages of our science and shows its significance for medicine.
Our colleagues provided great assistance in creating the textbook. At the All-Union Conference in Suzdal (1982), the structure was discussed and approved, and valuable wishes were expressed regarding the content of the textbook. Prof. VP Skipetrov revised the structure and edited the text of the 9th chapter and, in addition, wrote its sections relating to blood coagulation. Prof. V. S. Gurfinkel and R. S. Person wrote a subsection of the 6th floor “Regulation of movements”. Assoc. NM Malyshenko presented some new material for chapter 8. Prof. IDBoenko and his collaborators expressed many useful remarks and wishes as reviewers.
Employees of the Department of Physiology II MOLGMI named after N. I. Pirogov prof. L. A. M. Iyutina, associate professors I. A. Murashova, S. A. Sevastopolskaya, T. E. Kuznetsova, candidate of medical sciences / V. I. Mongush and L. M. Popova took part in discussion of the manuscript of some chapters, (I would like to express our deep gratitude to all these comrades.
The authors are fully aware that in such a difficult matter as the creation of a modern textbook, shortcomings are inevitable and therefore they will be grateful to everyone who expresses critical comments and wishes about the textbook. "
Corresponding Member of the USSR Academy of Medical Sciences, prof. G. I. KOSITSKY
Chapter 1 (- v
PHYSIOLOGY and ITS SIGNIFICANCE
Physiology(from rpew. physis - nature and logos - teaching) - the science of the life of the whole organism and its individual parts: cells, tissues, organs, functional systems. Physiology seeks to reveal the mechanisms of the implementation of the functions of a living organism, their relationship with each other, regulation and adaptation to the external environment, origin and formation in the process of evolution and individual development of an individual.
Physiological patterns are based on data on the macro- and microscopic structure of organs and tissues, as well as on biochemical and biophysical processes occurring in cells, organs and tissues. Physiology synthesizes specific information obtained by anatomy, histology, cytology, molecular biology, biochemistry, biophysics and other sciences, combining them into a single system of knowledge about the body. Thus, physiology is a science that implements systems approach, i.e. the study of the organism and all its elements as systems. The systematic approach focuses the researcher, first of all, on the disclosure of the integrity of the object and the mechanisms that provide e (mechanisms, i.e., on the identification of diverse link types complex object and bringing them together a single / p theoretical picture.
An object the study of physiology - a living organism, the functioning of which, as a whole, is not the result of a simple mechanical interaction of its constituent parts. The integrity of the organism arises and not as a result of the influence of some supra-material essence, unquestioningly subjugating all the material structures of the organism. Similar interpretations of the Integrity of the organism existed and still exist in the form of a limited mechanistic ( metaphysical) or no less limited idealistic ( vitalistic) approach to the study of life phenomena. The errors inherent in both approaches can only be overcome by studying these problems with dialectical materialist positions. Therefore, the regularities of the activity of the organism as a whole can be understood only on the basis of a consistently scientific worldview. For its part, the study of physiological laws provides rich factual material illustrating a number of tenets of dialectical materialism. The connection between physiology and philosophy is thus two-way.
Physiology and Medicine /
By revealing the basic mechanisms that ensure the existence of an integral organism and its interaction with the environment, physiology makes it possible to clarify and investigate the causes, conditions and nature of disturbances, the activity of these mechanisms during illness. It helps to determine the ways and means of influencing the body, with the help of which it is possible to normalize its functions, i.e. restore health. Therefore physiology is theoretical basis of medicine, physiology and medicine are inseparable. "The doctor assesses the severity of the disease by the degree of functional disorders, i.e., by the magnitude of the deviation from the norm of a number of physiological functions. Currently, such deviations are measured and quantified. Functional (physiological) studies are the basis of clinical diagnosis, as well as method of evaluating the effectiveness of treatment and prognosis of diseases.Examining the patient, establishing the degree of violation of physiological functions, the doctor sets himself the task of returning the e + and functions to normal.
However, the significance of physiology for medicine is not limited to this. The study of the functions of various organs and systems made it possible simulate these functions with the help of devices, devices and devices created by human hands. In this way, artificial kidney (hemodialysis machine). Based on the study of the physiology of the heart rhythm, an apparatus was created / for Electro stimulation heart, which ensures normal cardiac activity and the possibility of returning to work in patients with severe heart damage. Manufactured artificial heart and devices cardiopulmonary bypass(mashing "heart - lungs") ^ allowing you to turn off the patient's heart for the duration of a complex operation on the heart. There are devices for defib-1llation, which restore normal cardiac activity in death->1X violations of the contractile function of the heart muscle.
Research in the field of respiratory physiology made it possible to design an apparatus for controlled artificial respiration("iron lungs"). Devices have been created with the power of which it is possible to turn off the patient's breathing for a long time. Under the conditions of therapy, either: to maintain the life of the organism for years in case of damage to the respiratory system. Knowledge of the physiological patterns of gas exchange and transport of gases helped to create installations for hyperbaric oxygenation. It is used in fatal lesions of the system: the blood, as well as the respiratory and cardiovascular systems, and on the basis of the laws of brain physiology, methods have been developed for a number of complex neurosurgical operations. Thus, electrodes are implanted into the cochlea of a deaf person, according to which electrical impulses are received from artificial sound receivers, which to a certain extent restores hearing. ":
These are only a very few examples of the use of the laws of physiology in the clinic, and the significance of our science goes far beyond the limits of only "medical medicine".
The role of physiology is to ensure human life and activity in various conditions
The study of physiology is necessary for the scientific substantiation and creation of conditions for a healthy lifestyle that prevents diseases. Physiological patterns are the basis scientific organization of labor in modern production. Physio-yugia made it possible to develop a scientific substantiation of various MODES OF INDIVIDUAL RENUREMENTS and sports loads that underlie modern sports achievements. And not only sports. If you need to send a person into space or to settle him in the depths of the ocean, undertake an expedition to the north and south poles, reach the peaks of the Himalayas, master the tundra, taiga, desert, place a person in conditions of extremely high or low temperatures, move him to different time zones or " climatic conditions, then physiology helps to substantiate and ensure all necessary for the life and work of a person in such extreme conditions.
Physiology and technology
Knowledge of the laws of physiology was required not only for scientific organization, but also for increasing the productivity of labor. Over billions of years of evolution, nature, as is known, has reached the highest perfection in the design and control of the functions of living organisms. The use in technology of the principles, methods and methods that operate in the body opens up new prospects for technological progress. Therefore, at the junction of physiology and technical sciences, a new science was born - bionics.
Advances in physiology contributed to the creation of a number of other areas of science.
DEVELOPMENT OF PHYSIOLOGICAL RESEARCH METHODS
Physiology was born as a science experimental. Everything it obtains data by direct study of the vital processes of animal and human organisms. The founder of experimental physiology was the famous English physician William Harvey. v " .■
“Three hundred years ago, in the midst of the deep darkness and the now hard to imagine confusion that reigned in ideas about the activities of animal and human organisms, but illuminated by the inviolable authority of the scientific classical. heritage; doctor William Harvey spied on one of the most important functions of the body - blood circulation, and thus laid the foundation for a new department of exact human knowledge - animal physiology, ”wrote I.P. Pavlov. However, for two centuries after the discovery of blood circulation / Harvey, the development of physiology was slow. It is possible to list relatively few fundamental works of the 17th-18th centuries. This is the opening of the capillaries(Malpighi), statement of principle .reflex activity of the nervous system(Descartes), measurement of magnitude blood pressure(Health), wording of the law conservation of matter(M.V. Lomonosov), the discovery of oxygen (Priestley) and commonality of combustion and gas exchange processes(Lavoisier), opening " animal electricity", vol. e . the ability of living tissues to generate electrical potentials (Galvani), and some other works:
Observation as a method of physiological research.
The relatively slow development of experimental physiology during the two centuries following Harvey's work is explained by the low level of production and development of natural science, as well as by the difficulties of studying physiological phenomena through their ordinary observation. Such a methodological technique has been and remains the cause of numerous errors, since the experimenter must conduct the experiment, see and memorize many
Hj E. VVEDENSKY (1852-1922)
to: ludwig
:two complex processes and phenomena, which is a difficult task. Harvey's words eloquently testify to the difficulties that the method of simple observation of physiological phenomena creates: “The speed of cardiac movement does not allow us to distinguish how systole and diastole occur, and therefore it is impossible to know at what moment / in which part expansion and contraction occurs. Indeed, I could not distinguish systole from diastole, since in many animals the heart shows up and disappears in the blink of an eye, with the speed of lightning, so that it seemed to me once here systole, and here - diastole, another time - vice versa. Everything is different and inconsistent.”
Indeed, physiological processes are dynamic phenomena. They are constantly evolving and changing. Therefore, only 1-2 or, at best, 2-3 processes can be observed directly. However, in order to analyze them, it is necessary to establish the relationship of these phenomena with other processes that, with this method of investigation, remain unnoticed. In this regard, the simple observation of physiological processes as a research method is a source of subjective errors. Usually, observation makes it possible to establish "only the qualitative side of phenomena and makes it impossible to study them quantitatively.
An important milestone in the development of experimental physiology was the invention of the kymograph and the introduction of the method of graphic recording of blood pressure by the German scientist Karl Ludwig in 1843.
Graphic registration of physiological processes.
The method of graphic registration marked a new stage in physiology. It made it possible to obtain an objective record of the process under study, minimizing the possibility of subjective errors. At the same time, the experiment and analysis of the phenomenon under study could be carried out in two stages: During the experiment itself, the task of the experimenter was to obtain high-quality records - curves. The data obtained could be analyzed later, when the experimenter's attention was no longer diverted to the experiment. The method of graphic recording made it possible to record simultaneously (synchronously) not one, but several (theoretically an unlimited number) of physiological processes. "..
Quite soon after the invention of recording blood pressure, methods for recording the contraction of the heart and muscles (Engelman) were proposed, the method was introduced; stuffy transmission (Marey's capsule), which sometimes made it possible to record a number of physiological processes in the body at a considerable distance from the object: respiratory movements of the chest and abdominal cavity, peristalsis and changes in the tone of the stomach, intestines, etc. A method was proposed for recording vascular tone (Mosso plethysmography), changes in the volume of various internal organs - oncometry, etc.
Studies of bioelectric phenomena. An extremely important direction in the development of physiology was marked by the discovery of "animal electricity". The classic "second experiment" by Luigi Galvani showed that living tissues are a source of electrical potentials that can act on the nerves and muscles of another organism and cause muscle contraction. Since then, for almost a century, the only indicator of the potentials generated by living tissues [biotherapeutic potentials), was; a neuromuscular preparation of a frog. He helped to discover the potentials generated by the Heart during: its activity (the experience of K.eLliker and Muller), as well as the need for continuous generation of electrical potentials for the constant contraction of the Muscles (the experience of the “secondary reran mustache.” Mateuchi). It became clear that bioelectric potentials are not "random (side) phenomena in the activity of living tissues, but signals by which commands are transmitted in the body to and from the nervous system: to muscles and other organs and thus to living tissues I interact" with each other using "electric language". „
It was possible to understand this "language" much later, after the invention of physical devices that capture bioelectric potentials. One of the first such devices! was a simple phone. The remarkable Russian physiologist N.E. Vvedensky, using the telephone, discovered a number of the most important physiological properties of nerves and muscles. Using the phone, I managed to listen to the bioelectric potentials, i.e. to explore their way/observation. A significant step forward was the invention of a technique for objective graphic recording of bioelectric phenomena. The Dutch physiologist Einthoweg invented - a device that made it possible to register, on photo paper, the electrical potentials that arise during the activity of the heart - an electrocardiogram (ECG). In our country, the pioneer of this method was the largest physiologist, student of I.M. Sechenov and I.P. Pavlov, A.F. Samoilov, who worked for some time in the laboratory of Einthoven in Leiden, ""
Very soon, the author received a reply from Einthoven, who wrote: “I exactly fulfilled your request and read the letter to the galvanometer. Undoubtedly / he listened and accepted with pleasure and joy everything that you wrote. He did not suspect that he had done so much for humanity. But at the place where Zy says that he cannot read, he suddenly became furious ..: so that my family and I. even got excited. He shouted: What, I can't read? This is a terrible lie. Am I not reading all the secrets of the heart?” "
Indeed, electrocardiography from physiological laboratories very soon passed into the clinic as a very perfect method for studying the state of the heart, and many millions of patients today owe their lives to this method.
Subsequently, the use of electronic amplifiers made it possible to create compact electrocardiographs, and telemetry methods make it possible to record the ECG of astronauts in orbit, from athletes on the track and from patients in remote areas, from where the ECG is transmitted via telephone wires to large cardiological institutions for comprehensive analysis.
"Objective graphic registration of bioelectric potentials has served as the basis for the most important section of our science - electrophysiology. A major step forward was the proposal of the English physiologist Adrian to use electronic amplifiers to record biocentric phenomena. The Soviet scientist V.V. Pravdicheminsky first registered the biocurrents of the brain - received electro-schephalogram(EEG). This method was later improved by the German scientist Behr-I ipoM. Currently, electroencephalography is widely used in the clinic, as well as a graphic recording of muscle electrical potentials ( electromyography ia), nerves and other excitable tissues and organs. This made it possible to conduct a fine analysis of the functional state of these organs and systems. For physiology itself, smeared methods were also of great importance; they made it possible to decipher the functional and structural mechanisms of the activity of the nervous system and other tissue organs, the mechanisms of regulation of physiological processes.
An important milestone in the "development of electrophysiology" was the invention microelectrodes, e. the thinnest electrodes, the tip diameter of which is equal to fractions of a micron. These electrodes can be inserted directly into the cell with the help of appropriate micromanipulator devices and bioelectric potentials can be recorded intracellularly. \microelectrodes made it possible to decipher the mechanisms of generation of biopotentials, i.e. processes that take place in cell membranes. Membranes are the most important formations, since through them the processes of interaction of cells in the body and individual elements of the cell with each other are carried out. The Science of Biological Membrane Functions - membrapology - became an important branch of physiology.
