Physiology (from the Greek. Physis - nature and logos - teaching) is one of the oldest natural sciences. It studies the vital activity of the whole organism, its parts, systems, organs and cells in close relationship with the surrounding nature. The history of physiology includes two periods: empirical and experimental, which can be divided into two stages — before I. P. Pavlov and after it.

EMPIRICAL PERIOD

The first ideas about the work of individual organs of the human body began to take shape in ancient times and are set forth in the writings of philosophers and doctors of the ancient East, ancient Greece and ancient Rome that have come down to us.

During the period of the classical Middle Ages, when church scholasticism prevailed and attempts of an experienced knowledge of nature were cruelly persecuted, the development of natural science was observed to stagnate. In the Renaissance, anatomical, physiological, and natural science studies by A. Vesalius, M. Servet, R. Colombo, J. Fabricius, G. Fallopyy, G. Galilei, S. Santorio, and others prepared the ground for future discoveries in the field of physiology.

EXPERIMENTAL PERIOD

Physiology as an independent science based on an experimental method of research leads its own. beginning from the work of 'William Garvey (Harvey William, 1578-1657), who mathematically calculated and experimentally substantiated the theory of blood circulation (1628).

The rapid development of the natural sciences at that time was associated with the needs of the young bourgeois class, interested in the development of industrial production. The laws of mechanics established in the experiment, with which they then tried to explain all the phenomena of the material world, were transferred to living beings (yatromechanics and iatrophysics). Thus, the physiology of the XVII-XVIII centuries. it was mechanistic, metaphysical in nature, which, for that stage of development of science, was still a progressive phenomenon.

From the standpoint of the laws of mechanics, scientists tried to explain the work of gelnochnogo apparatus, the mechanism of ventilation of the lungs, kidney function, etc.

The concept of animal automatons was very popular, since worn by Rene Descartes (Descartes Rene, 1596–1650), who strained principles of the mechanistic movement and on the nervous system of the men. He put forward the idea of ​​reflex as a reflection (the term reflexus introduced in physiology of Czech scientists I. Prokhaska! 1749- ^ 1820) from the brain "Animal spirits," moving from one nerve to another, and thus By this, he developed in the simplest form a reflex arc. Using laws Optics, Descartes tried to explain the work of the human eye (Fig. 126). Furs Descartes' nistical views for that time were progressive and had a positive impact on the further development of natural science.

At the same time, Descartes believed that thinking is the ability to shi and has nothing to do with matter, the only property of which swarm he considered the length. His dualism was reflected in the outlook of many scientists of subsequent generations.

An important role in the development of physiology was played by the Swiss naturalist, physician and poet, Albrecht Galler (Haller, Albrecht von, 1708–1777). He tried to understand the essence of the process of respiration in the lungs, established three properties of muscle fibers (elasticity, contractility and irritability), determined the dependence of the force of contraction on the size of the stimulus and thereby developed Descartes' ideas about reflex. Galler was the first to notice that the heart is contracting involuntarily by the force that is in the heart.

An outstanding achievement of the XVIII century. the discovery of bioelectric phenomena (“animal electricity”, 1791) by the Italian anatomist and physiologist Luigi Galvani (Galvani, Luigi Aloisio, 1737-1798), which marked the beginning of electrophysiology.

K XIX c. A lot of physiological knowledge was accumulated. However, metaphysical thinking continued to dominate in science, which, having exhausted its progressive role, at this stage in the development of science led to the development of idealistic (for example, vitalistic) concepts.

One of the founders of experimental medicine, the French physiologist Francois Magendie (Magen-die, Francois, 1783-18555), actively advocated against the notion of a special “vital force”. Continuing the research of I. Prokhaski, he proved the separate existence of sensory (posterior roots) and motor (anterior roots of the spinal cord) nerve fibers (1822), which asserted the correspondence between structure and function (the Bell – Majandi law).

In Russia, the creation of the fundamentals of the materialist trend in physiology is connected with the activity of Aleksey Matveyevich Filomafitsky:. (1807-1849) - the founder of the Moscow physiological school. In 1833 he defended his doctoral thesis “On the Breath of Birds”, then worked in Germany in the laboratory of I. Müller for two years and in 1835 became a professor at Moscow University.

A.M. Filomafitsky was one of the first propagandists of the experimental method in Russian physiology and medicine. Together with N. I. Pi-horny, he developed a method of intravenous anesthesia; using the vivisection technique, he studied the physiology of respiration, digestion, and blood transfusion (Treatise on Blood Transfusion, 1848); created blood transfusion apparatus, ether anesthesia mask and other physiological devices. A.M. Filomafitsky is the author of the first Russian textbook "Physiology, published to guide its students" (1836).

Among the founders of physiology and experimental medicine, a prominent place is occupied by the German naturalist Johannes Muller (Miiller, Johannes Peter, 1801-1858), a member of Prussia (1834) and a foreign correspondent member of the Petersburg Academy of Sciences (1832). He owns fundamental research and discoveries in the field of physiology, pathological anatomy, and embryology. In 1833, he formulated the main provisions of the reflex theory, which found further development in the writings of I. M. Sechenov and I. P. Pavlov.

I. Müller made a great contribution to the materialistic knowledge of nature. He created a unique in the number of followers and their contribution to science scientific school. To her belong R. Virkhov, G. Helmholtz, F. Henle, E. DuBois-Raymond, E, Pfluger, T. Schwann. Many Russian scientists worked in his laboratory: A. M. Filomafitsky, I. M. Sechenov and others.

In the middle of the XIX century. The development of physiology was closely related to the fundamental importance of discoveries and generalizations in the fields of physics, chemistry, and biology (see Table 10). On their basis, new methods and techniques of physiological experiment were developed.

In the laboratory of the outstanding German physiologist Karl Ludwig (Ludwig, Karl FW, 1816–1895), the creator of one of the largest schools in the history of physiology, a kimograph (1847) and a mercury manometer for recording blood pressure, a blood clock for measuring blood flow velocity, were constructed plethysmograph, determining the blood supply to the limbs and other devices for physiological experiments.

The founder of the neuromuscular physiology, the German physiologist Emile Dubois-Reymond (Du Bois-Reymond, Emile, 1818-1896), continuing the research started by Galvani and Volta, developed new methods of the electrophysiological experiment and discovered the laws of stimulation and the appearance of an electroton (1848). He also formulated the molecular theory of biopotentials.

The German physicist, mathematician and physiologist Hermann Helmholtz (Helm-holtz, Herman, 1821-1894), who laid the foundation for the physiology of excitable tissues, made major discoveries in the field of physiological acoustics and physiology of vision, studied the processes of muscle contraction (the phenomenon of tetanus, 1854) and for the first time measured the speed of the excitation along the nerve of the frog (1850) (see Table 10).

The outstanding French physiologist Claude Bernard (Bernard, Claude, 1813–1878) studied in detail the physiological mechanisms of secretion and the importance of the digestive properties of saliva, gastric juice and pancreatic secretions for a healthy and diseased organism, thus laying the foundations of experimental pathology. He created the theory of sugar diabetes (the highest prize of the French Academy of Sciences, 1853), studied the nervous regulation of blood circulation, put forward the concept of the significance of the constancy of the internal environment of the body (the basis of the theory of homeostasis).

Thus, in the second half of the nineteenth century. great strides have been made in studying the functions of individual organs and systems, in the study of some of the simplest mechanisms of heart regulation and activity (E. Weber, I. F. Tsion, I. P. Pavlov), vessels (A. P. Walter, K. Bernard, K. Ludwig, I. F. Zion, F., V. Ovsyannikov), respiration (N. A. Mislavsky), skeletal muscles (F. Majandi, I. M. Sechenov, N. E. Vvedensky) and other organs and systems. But all this knowledge remained fragmented; they were not united by theoretical generalizations about the interconnection of various functions of the body among themselves. This was a period of accumulation of information, and therefore the analysis of phenomena prevailed (analytical physiology), however, there was already a tendency towards synthesis, which was manifested in the desire to study the functions of the central nervous system and, above all, reflexes.

An outstanding contribution to the development of reflex theory, which is one of the basic theoretical concepts of physiology and medicine, was made by the great Russian scientist, an eminent representative of the Russian physiological school and the founder of scientific psychology, Ivan Mikhailovich Sechenov (1829-1905).

In 1856, he graduated from the Medical Faculty of Moscow University and was sent abroad, where he received training for a professorship in the laboratories of I. Müller, E. DuBois-Reymond, C. Ludwig, K. Bernard. Upon returning to Russia in 1860, I. M. Sechenov defended his doctoral thesis "Materials for the future physiology of alcohol intoxication."

His work on the physiology of respiration and blood, gas exchange, the dissolution of gases in liquids and energy exchange laid the foundations for future aviation and space physiology. However, his works in the field of physiology of the central nervous system and neuromuscular physiology are of particular importance.

At the time of I. M. Sechenov, ideas about the work of the brain were very limited. In the middle of the XIX century. there has not yet been a theory of the neuron as a structural unit of the nervous system. It was created only in 1884 by the Spanish histologist, the Nobel laureate, the prize (1906) S. Ramon-i-Kahal (Ramon-y-Cajal, Santjago, 1852-1934). There was no concept of the synapse, which was introduced in 1897 by the English physiologist C. Sherrington (Sherrington, Charles Scott, 1857-1952), who formulated the principles of the neural organization of a reflex arc. Scientists of that time did not apply reflex principles to brain activity.

Sechenov was the first to put forward the idea of ​​a reflex basis of mental activity and convincingly proved that “all acts of conscious and unconscious life according to the method of origin are reflexes”.

The central (Sechenov) inhibition (1863) discovered by him for the first time demonstrated that, along with the process of excitation, there is another active process - inhibition, without which the integrative activity of the central nervous system is unthinkable.

A classic generalization of the research of I. M. Sechenov was his work “Reflexes of the Brain” (1863), which IP Pavlov called “the ingenious stroke of Russian scientific thought” (Fig. 127). Its essence is succinctly expressed in the original names, modified as required by censorship: “Attempt to reduce the mode of origin of psychic phenomena to physiological bases” and “Attempt to introduce physiological bases into mental processes”. This scientific work was written by I. M. Sechenov at the request of the poet N. A. Nekrasov, editor of the Sovremennik magazine. Before I. M. Sechenov the task was set: to give an analysis of the modern state of natural science. Progressive scientific views of the author, confirmed by the description of physiological experiments, forced the censor to recognize this work as dangerous: his publication in the journal Sovremennik was prohibited. However, in the same 1863, the work of I. M. Sechenov was published in Medical Herald, then published in a separate publication and received a tremendous resonance in the public and academic life of Russia.

Defending the principles of materialistic natural science, I. M. Sechenov argued that “the environment in which an animal exists is a factor determining the organization ... an organism without an external environment ... is impossible, therefore the scientific definition of an organism should also include an environment affecting him. " IP Pavlov wrote on this subject: “... together with Ivan Mikhailovich and the regiment of my dear employees, we acquired for the mighty power of physiological research, instead of half, the whole inseparable animal organism. And this is entirely our Russian unquestionable merit in world science, in universal human thought. ”

Sechenov created a large physiological school in Russia. His disciples were B. F. Verigo, N. E. Vvedensky, V. V. Pashutin, G. V, Khlopin, M. N. Shaternikov, and many others.

Nikolai Evgenievich Vvedensky (1852–1922) —the successor of I. M. Sechenov in the Department of Physiology of St. Petersburg University — made a significant contribution to the development of the physiology of excitable tissues and the nervous system as a whole. In 1887 he defended his doctoral thesis "On the relationship between irritation and arousal with tetanus." Using a telephone, he first heard the rhythmic excitement in the nerve (1884). Studying the phenomenon of tetanus, showed the ability of the myonevral synapse to transform impulses and, on this basis, discovered the phenomena of optimum and pessnumma (Wedensky inhibitor) stimulation (1886). Vvedensky introduced the concept of lability and created the doctrine of parabiosis, which is set out in his monograph "Excitation, Inhibition and Anesthesia" (1901). The further development of the physiology of excitable tissues is connected with the works of A. A. Ukhtomsky, B: F. Verigo, V. Yu. Chagovets, D. N. Nasonov and others.

Analytical nature of physiological science in the second half of the XIX century. led to the division of phenomena occurring in a living organism into two categories: 1) "internal", vegetative processes (metabolism, respiration, blood circulation, etc.) "and - 2). "Animals" (animal), defining the behavior of animals, which the physiology of the time could not yet; to explain. This led either to vulgar materialism (FK Bruchner, I, Moleschott, K. Vogt), or to agnosticism, i.e., the statement that behavior and consciousness are unknowable (E. DuBois-Reymond).

In order to bring the physiology out of the impasse of the analytical method, a fundamentally new approach to the knowledge of the activity of living organisms was needed. For the first time, its elements are formed in the works of I. M. Sechenov, who was the first to be able to apply the evolutionary method to the study of mental functions. The turning point is connected with the work of the great Russian scientist Ivan Petrovich Pavlov (1849–1936) —the creator of the theory of higher nervous activity, the founder of the largest physiological school of modern times, and the innovator of research methods in physiology (Fig. 128).

In 1879, I.P. Pavlov graduated from the Medical Surgical Academy, and was invited. S.P. Botkin to the physiological laboratory at his clinic, where he supervised pharmacological and physiological studies. In the laboratory of S. P. Botkin, I. P. Pavlov completed his doctoral thesis "Centrifugal nerves of the heart" (1883), and then began research on the physiology of digestion. For two years (1884–1886) he worked in the laboratories of R. Heyden-Gain and K. Ludwig in Germany, after which he returned to the Botkin laboratory.

In 1890, I.P. Pavlov was elected professor of pharmacology (and in 1895, professor of physiology) at the Military Medical Academy (where he worked until 1925) and almost simultaneously as head of the physiological department at the Institute of Experimental Medicine in St. Petersburg.

Studies of IP Pavlov in the physiology of the cardiovascular and digestive systems and the higher parts of the central nervous system are classical.

In 1897, his “Lectures on the work of the main digestive glands” were published, which were a summary of the research in the field of digestion — a section of physiology that was practically re-created by him. Despite the language barrier, the work of IP Pavlov and his collaborators at the Institute of Experimental Medicine became known throughout the world. At the Karolinska Institute (Sweden), which in 1901 received the right to award Nobel Prizes in Physiology and Medicine, the name of I. P. Pavlov was often named in the lists of candidates for laureates. However, one circumstance raised a question: I.P. Pavlov himself rarely figured as a coauthor in the works of your own employees, and Karolinsky in-. The institute sent a representative of professor Karl T-Gertstedt to St. Petersburg to find out who is in charge of such a fruitful scientific activity of this team. As a result, in 1904 Pavlov was awarded the Nobel Prize in Physiology and Medicine "in recognition of his work on the physiology of digestion, which allowed us to change and expand our knowledge in this area."

Proceeding from the thesis “for a natural scientist, everything is in the method,” IP Pavlov introduced the method of a chronic experiment into physiological research, which made it possible to study a complete, practically healthy animal.

Experiments on "chronically operated" animals were carried out by physiologists and before Pavlov. However, they were inferior either by design or by the method of implementation. Thus, the method of an isolated “small ventricle,” proposed by R. Heidenhain (Heidenhain, Rudolf Peter Heinrich, 1834–1897), deprived an isolated area of ​​innervation. The method of chronic experiment proposed by IP Pavlov allowed him experimentally to substantiate the principle of nervism — the idea of ​​the crucial role of the nervous system in regulating the functional state and activity of all organs and systems of the body.

The methodological basis of his concept was three basic principles: the unity of structure and function, determinism, analysis and synthesis. Studying the behavior of animals, I. P. Pavlov revealed reflexes of a new type, which are formed and fixed under certain environmental conditions. Pavlov called them conditional, in contrast to the already known innate reflexes, which are from birth in all animals of a given species (Pavlov called them unconditional). It was also shown that conditioned reflexes are produced in the cerebral cortex, which made it possible to experimentally study the activity of the cerebral cortex in normal and pathological conditions. The result of these studies was the creation of a materialistic theory of higher nervous activity, one of the greatest achievements of natural science in the 20th century.

The activity of IP Pavlov was an epoch in the development of physiology. In early 1921, he headed the physiological laboratory of the Institute of Experimental Medicine (in Petrograd, now St. Petersburg). The scientific school created by him enriched the physiology with new creative achievements (see p. 333).