The end of the 19th and the beginning of the 20th century were marked by major achievements in the field of the physiology of digestion.
Pavlov paid much attention to the method of work: he created a unified method for cognizing physiological patterns, combining the analytical approach that had prevailed before with the synthetic one he introduced.Thanks to the development of a new method studies of digestive processes Ivan Petrovich Pavlov and his students studied the basic patterns of activity of various parts of the digestive canal.
Rice. Ivan Petrovich Pavlov
On the basis of experimental material, I. P. Pavlov created the doctrine of the work of the main digestive glands and the activity of the digestive system as a whole, which is still the theoretical basis of physiology.
The results of IP Pavlov's research on the physiology of digestion are summarized in his book "Lectures on the work of the main digestive glands", published in 1897 and which has become a classic work.
For outstanding achievements in the field of studying the physiology of digestion in 1904, I.P. Pavlov is awarded the Nobel Prize.
Rice. IP Pavlov in the audience of the Department of Physiology of the Military Medical Academy after the demonstration of the lecture experiment. 1912
works by I. P. Pavlov
Before the works of Pavlov, the study of knowledge about digestion was limited to fragmentary information about individual moments of the functioning of the digestive system. Information was obtained mainly by observation or throughexperiments on anesthetized animals with a broken connection between parts of the body.
chronic experiment method
I. P. Pavlov introduced the new kind experiment - chronic, on an intact or previously operated animal.
He conducted research on the functioning of the glands of the gastrointestinal tract on a healthy non-anesthetized animal in a chronic experiment while maintaining the continuous operation of all parts of the digestive system of the animal's body.
Pavlov studied the basic patterns of the work of individual organs of the gastrointestinal tract, the interaction of these organs in the process of the entire digestive system, and determined the main physiological mechanisms of its regulation. An important discovery was the definition of the regulatory role of the central nervous system in ensuring the holistic activity of the digestive system.
Rice. Pavlov's dog (Museum named after Timiryazev)
artificial fistula method
It took more than 10 years to develop a technique for obtaining an artificial fistula (hole) of the gastrointestinal tract. It was extremely difficult to perform such an operation, since the juice flowing from the intestines digested the intestines and the abdominal wall. I. P. Pavlov learned to insert excretory tubes so that there were no erosions, and he could receive pure digestive juice throughout the entire gastrointestinal tract: from the salivary gland to the large intestine.
Rice. Chronic experiment with the installation of intestinal fistula
imaginary feeding experiments
In experiments with imaginary feeding Pavlov proved that the secretion of gastric juice, caused by the action of food on the receptors of the oral cavity, has a reflex character.
With "sham feeding" the esophagus is cut so that food does not enter the stomach.
Rice. Imaginary feeding
If the vagus nerves (the parasympathetic nerves that connect the medulla oblongata (CNS) with the digestive glands) are cut in a dog with the operations described above, then imaginary feeding will subsequently no longer cause gastric juice to be released.
IP Pavlov concluded: food excites the taste apparatus, through the taste nerves, the excitation is transmitted to the medulla oblongata, and from there through the vagus nerves to the gastric glands, i.e. reflex action of receptors of the oral cavity on the glands stomach.
This method was proposed by I.P. Pavlov in 1890 to study the role of the central nervous system in the regulation of gastric secretion, as well as pure digestive juices can be examined.
Studies of the work of the salivary glands
Getting Started salivary glands, Pavlov had, perhaps, the best initial base of all the issues that he dealt with in the field of digestive physiology.
By the time the research began, it was known about the presence of innervation of the salivary glands that a huge number of various receptors. However, it was erroneously believed that the secretion of saliva is a response to the general excitation of receptors in the oral cavity.
Using a chronic experiment, Pavlov found that the secretion of saliva depends on specific stimuli. Besides, after analyzing the results of the experiments, Pavlov came to the conclusion that, depending on the stimuli, the properties of the secretedsaliva: it can perform a digestive, protective or sanitary-hygienic function. These changes are adaptive.
study of the functions of the stomach
To study the work of the stomach, Pavlov created a method known as the Pavlov Small Stomach Operation.
In the stomach cavity, a bag, the so-called small stomach, is operatively sutured from the main mass of the stomach, with a cavity isolated from the large stomach, but having a common wall of the muscular and serous layers with the latter.
Rice. Scheme of surgery to isolate the small ventricle and a dog with a Pavlovian ventricle (a - fistula tube)
The operation performed in this way preserved both nutrition and innervation of the created ventricle, making it completely identical to the large main stomach, preserving and repeating all its functional functions without exception (juice secretion, motility, and other manifestations of activity), at the same time, not allowing food ingress.
The creation of an isolated ventricle made it possible to study in detail the processes occurring in the stomach and distinguish two phases of gastric juice secretion: neuro-reflex and humoral-clinical.
Based on the results of these studies, IP Pavlov created the work "Lectures on the work of the main digestive glands" in 1897.
Basic principles of Pavlovian physiology
- The body is one, the whole:
A living organism is a single whole in which the activity of cells, tissues, organs, physiological systems is coordinated and connected. The body has the ability to self-regulate functions. - The unity of the organism and the environment.
The body is in constant interaction with the environment. There is a constant exchange of matter and energy between the environment and the body. To survive, an organism must constantly adapt to its environment. - The principle of nervosa.
The connection of the organism with the external environment occurs continuously due to simple and complex relationships: simple ones are carried out with the participation of innate unconditioned reflexes, complex ones - due to acquired conditioned reflexes. However, a person is also influenced by the social environment. In human interactions with the social environment, the most important role belongs to the so-called second signal system, which underlies human speech and thinking.
nervism principle
Pavlov, as a follower of Sechenov, dealt a lot with nervous regulation.The studies of IP Pavlov made a significant contribution to the development of the principle of nervism in physiology.Pavlov first defined the principle of nervism in his doctoral dissertation: "Nervism should be understood as a physiological trend that seeks to extend the influence of the nervous system to as many activities of the body as possible."
I. P. Pavlov established the importance of the nervous system in the regulation of the functions of the circulatory system and the gastrointestinal tract, for the first time discovered the influence of the nervous system on metabolic processes occurring in organs and tissues (the trophic effect of the nervous system), showed that the activity of the nervous system ensures unification ( integration) of the functions of individual organs and systems of the body and its relationship with the external environment.
One of the most important provisions of IP Pavlov's work is the elucidation of the role of the cerebral cortex in the regulation of body functions.
None of the Russian scientists of the XIX-XX centuries, even D.I. Mendeleev, did not receive such fame abroad as academician Ivan Petrovich Pavlov (1849-1936). “This is a star that illuminates the world, shedding light on paths not yet explored,” HG Wells said about him. He was called "a romantic, almost legendary personality", "a citizen of the world". He was a member of 130 academies, universities and international societies. He is considered the recognized leader of the world physiological science, the favorite teacher of doctors, a true hero of creative work.
Ivan Petrovich Pavlov was born in Ryazan on September 26, 1849 in the family of a priest. At the request of his parents, Pavlov graduated from a theological school, and in 1864 entered the Ryazan Theological Seminary.
However, he was destined for a different fate. In his father's extensive library, he once found a book by G.G. Levi's "Physiology of Everyday Life" with colorful illustrations that struck his imagination. Another strong impression on Ivan Petrovich in his youth was made by a book, which he later remembered with gratitude all his life. It was a study of the father of Russian physiology, Ivan Mikhailovich Sechenov, "Reflexes of the brain." Perhaps it would not be an exaggeration to say that the theme of this book was the leitmotif of Pavlov's entire creative activity.
In 1869, he left the seminary and first entered the faculty of law, and then transferred to the natural department of the Faculty of Physics and Mathematics of St. Petersburg University. Here, under the influence of the famous Russian physiologist Professor I.F. Ziona, he forever connected his life with physiology. After graduating from the university, I.P. Pavlov decided to expand his knowledge of physiology, in particular, human physiology and pathology. To this end, in 1874 he entered the Medical and Surgical Academy. Having brilliantly finished it, Pavlov received a two-year trip abroad. Upon arrival from abroad, he devoted himself entirely to science.
All works on physiology carried out by I.P. Pavlov for almost 65 years, are mainly grouped around three sections of physiology: the physiology of blood circulation, the physiology of digestion and the physiology of the brain. Pavlov introduced into practice a chronic experiment that made it possible to study the activity of a practically healthy organism. With the help of the developed method of conditioned reflexes, he established that the basis of mental activity is the physiological processes occurring in the cerebral cortex. Pavlov's studies of higher physiology nervous activity rendered big influence on the development of physiology, psychology and pedagogy.
Works by I.P. Pavlov on blood circulation are mainly associated with his activities in the laboratory at the clinic of the famous Russian doctor Sergei Petrovich Botkin from 1874 to 1885. Passion for research completely absorbed him during this period. He abandoned the house, forgot about material needs, about his suit and even about his young wife. His comrades more than once took part in the fate of Ivan Petrovich, wanting to help him in some way. Once they collected some money for I.P. Pavlov, wanting to support him financially. I.P. Pavlov accepted comradely help, but with this money he bought a whole pack of dogs in order to set up an experiment of interest to him.
The first serious discovery that made him famous was the discovery of the so-called amplifying nerve of the heart. This discovery served as the initial impetus for the creation of the scientific theory of nervous trophism. The whole cycle of works on this topic was formalized in the form of a doctoral dissertation entitled "Centrifugal nerves of the heart", which he defended in 1883.
Already during this period, one fundamental feature of the scientific work of I.P. Pavlova - to study a living organism in its holistic, natural behavior. The work of I.P. Pavlova in the Botkin laboratory brought him great creative satisfaction, but the laboratory itself was not convenient enough. That's why I.P. Pavlov gladly accepted in 1890 the offer to take over the department of physiology at the newly organized Institute of Experimental Medicine. In 1901 he was elected a corresponding member, and in 1907 a full member of the St. Petersburg Academy of Sciences. In 1904, Ivan Petrovich Pavlov received the Nobel Prize for his work on digestion.
Pavlov's teaching on conditioned reflexes was the logical conclusion of all those physiological experiments that he did on blood circulation and digestion.
I.P. Pavlov looked into the deepest and most mysterious processes of the human brain. He explained the mechanism of sleep, which turned out to be a kind of special nervous process of inhibition that spreads throughout the entire cerebral cortex.
In 1925 I.P. Pavlov headed the Institute of Physiology of the Academy of Sciences of the USSR and opened two clinics at his laboratory: nervous and psychiatric, where he successfully applied the experimental results obtained by him in the laboratory for the treatment of nervous and mental diseases. A particularly important achievement of the last years of I.P. Pavlov was the study of the hereditary properties of certain types of nervous activity. To address this issue, I.P. Pavlov significantly expanded his biological station in Koltushi near Leningrad - a real city of science - for which the Soviet government allocated more than 12 million rubles.
The teachings of I.P. Pavlov became the foundation for the development of world science. In America, England, France and other countries, special Pavlovian laboratories were created. February 27, 1936 Ivan Petrovich Pavlov died. After a short illness, he died at the age of 87. The funeral according to the Orthodox rite, according to his will, was performed in the church in Koltushi, after which a farewell ceremony took place in the Tauride Palace. A guard of honor was installed at the coffin of scientists from universities, technical universities, scientific institutes, members of the Presidium of the USSR Academy of Sciences.
Ivan Petrovich Pavlov (1849—1936),
scientist-physiologist, the first Russian Nobel Prize winner (in medicine).
The son of a Ryazan priest, Ivan Pavlov studied at the natural department of the Physics and Mathematics Faculty of the University in St. Petersburg.
Pavlov studied very successfully and attracted the attention of professors throughout the years of study at the university. In the 2nd year of study, he was assigned a regular stipend, in the 3rd year he already received an imperial stipend, which was twice as much as usual.
Pavlov chose animal physiology as his main specialty, and chemistry as an additional one.
Pavlov's research activity began early. As a fourth-year student, he studied the nerves in the lungs of a frog, studied the effect of the laryngeal nerves on blood circulation. students
Pavlov brilliantly graduated from the university, receiving the degree of candidate of natural sciences.
Pavlov believed that animal experimentation is necessary in resolving many complex and unclear issues of clinical medicine.
In 1890, Pavlov became a professor at the Military Medical Academy.
Pavlov carried out classical works on the physiology of the main digestive glands, which brought him worldwide fame and were awarded the Nobel Prize in 1904. It was the first prize in the history of mankind awarded for research in the field of medicine. A significant part of his work on conditioned reflexes immortalized the name of Pavlov and glorified Russian science.
What is Pavlov's dog?
Studying the work of the salivary glands, Pavlov noticed that the dog salivates not only at the sight of food, but also if it hears the steps of a person carrying it. What does this mean?
The secretion of saliva to food that has entered the mouth is the body's response to a certain irritation, occurs "by itself" and always manifests itself.
The steps of a man who was feeding a dog at a certain hour signaled: "Food." And in a dog, a conditioned connection was developed in the cerebral cortex: steps - food. Saliva began to stand out not only at the sight of food, but also at the sounds signaling its approach.
For the emergence of a conditioned reflex, it is necessary that a connection be formed in the cerebral cortex between two stimuli - conditioned and unconditioned. Saliva is secreted on food. If, while giving food (unconditioned stimulus), at the same time ring a bell (conditioned stimulus) and do this many times, then a connection will appear between sound and food. Formed new connection between different parts of the cerebral cortex. As a result, even just at the sound of a bell, the dog begins to salivate.
The irritant can be light and darkness, sounds and smells, heat and cold, etc.
The dog salivates at the call: it has developed a conditioned reflex. If you light a light bulb before the call, then a new conditioned reflex is developed - to the light. But the reflex can disappear, slow down. Braking is of great importance in the life of the body. Thanks to him, the body does not respond to any conditioned irritation.
The brain is based on a combination of excitation and inhibition.
Irritations perceived by the senses are a signal of the environment surrounding the body.
Animals have such a system of signals, and humans also have it. But man has another signaling system, more complex and more perfect. She worked out in him in the process historical development and it is precisely with it that the fundamental differences between the higher nervous activity of man and any animal are connected. It arose among people in connection with social work and is associated with speech.
The Pavlovian doctrine of higher nervous activity is a whole era in science. His teachings had an enormous impact on the work of physiologists around the world.
On his tombstone are the words: “Remember that science demands from a person his whole life. And if you had two lives, then they would not be enough for you.” .
Many scientific institutes and higher educational establishments are named after the great physiologist. educational establishments. New scientific institutions were organized for further development scientific heritage of IP Pavlov, including the largest Moscow Institute of Higher Nervous Activity and Neurophysiology of the USSR Academy of Sciences.
Prof. H. S. Koshtoyants
Ivan Petrovich Pavlov for his long journey scientific work left a deep impression in many areas of theory and practice. He created anew a number of chapters of modern physiology, a new direction of experimental therapy, he passionately fought for objective methods of research in one of the most difficult areas of knowledge - psychology. He is credited with the greatest merit of creating the world's largest physiological school, which has no equal in terms of creative charge and size. Analysis of scientific creativity and appearance of Pavlov as a citizen Soviet Union, proud of the consciousness of belonging to the great family of the peoples of the USSR, should be the task of many researchers. In this article we will try to outline the main line of Pavlov's scientific activity.
I. P. Pavlov.
At the "monument to the dog", opened in the courtyard of the Institute of Experimental Medicine.
Experimental animals of the physiological laboratory.
Dogs with gastric fistula: I - operated according to the method of Acad. I. P. Pavlova (“empty stomach”), a - the place of transection of the esophagus, b - fistula tube through which juice flows; I I - operated according to the Heidenhain method ("small stomach"), c - separated part of the stomach with a fistula tube.
Experimental animal in the machine.
Physiological laboratory.
Pavlov is a bright representative of experimental natural science. The physiological experiment, "observation and observation", the facts are the air that Pavlov, the researcher of nature, breathed. He was organically alien to reasoning about the phenomena of nature, not based on reliable experience.
Pavlov clearly showed that the newly created ways and methods of experimental study of nature reveal new aspects of phenomena that could not be shown with previous methods of research. Pavlov's work in this respect can be a classic example of how the creation of new approaches to the study of phenomena puts our knowledge on a new, higher level. Pavlov assessed the methods of studying digestion that existed before him and developed by him (in lectures on the work of the main digestive glands in 1897).
“An obstacle to early research was the lack of methodology. It is often said, and not without reason, that science moves in shocks, depending on the progress made by the methodology. With each step of the methodology forward, we seem to rise a step higher, from which a wider horizon opens up to us, with previously invisible objects. Therefore, our first task was to develop a methodology.”
Having correctly solved the problem of new methodological approaches, having created research methods closest to the conditions of the whole organism, Pavlov and his colleagues quickly made a number of major scientific discoveries. A group of works by Pavlov and his students in the field of physiology of the main digestive glands brought order to the "chaos" of ideas that was in the doctrine of digestion before Pavlov.
To eliminate the absolute insufficiency of all previous studies, which was evidenced by the centuries-old history of the study of digestion from experiments on the digestion of birds by the Italian Academia del Cimento and to the development of an artificial gastric fistula in a dog (Basov, 1842), Pavlov demanded that a number of conditions be met for obtaining gastric juice at any time , in its purest form, exact definition its quantity, the proper functioning of the digestive canal and monitoring the preservation of the animal in a healthy state. The fulfillment of all these conditions was devoted to the development of the method of an isolated (solitary) ventricle, which was carried out by Pavlov (1879) and independently by the German scientist Heidenhain (1880).
Later, methods of chronic pancreatic fistula, the method of imaginary feeding, etc. were developed. All this taken together allowed Pavlov and his students to make a number of major discoveries: they proved the basic patterns of the quantitative and qualitative response of glandular cells to one or another type of food irritation, which found their expression in classical Pavlovian contractions; they showed harmony and consistency in the work of various parts of the digestive tract; they discovered the role of the nervous system in regulating the work of the digestive glands, which was the beginning of great work in the field of conditioned reflexes; they made a number of major observations and discoveries that formed the basis of modern views on the nature of enzymatic processes (discovery of enterokinase); Finally, these works showed the great importance of the operative-surgical method. Pavlov's book "Lectures on the work of the main digestive glands" became a classic work that won worldwide fame, and Pavlov received the Nobel Prize (1904) for this group of works.
The results achieved by Pavlov in the development of methods for studying the digestive glands and firmly established in the everyday life of modern physiological institutions are important in the sense of asserting the enormous importance of a holistic study of the animal organism. This is the great advantage of Pavlov over his predecessors (Gelm, Bomoi, Basov, Blondlot, Heidenhain), who were involved in the development of the so-called fistula technique. The greatness of Pavlov is not that he improved the already existing methods of fistula technique, but that he saw in this the basis for a holistic study of physiological processes. This exceptionally important biological trend in the holistic study of the organism characterizes not only the period of work on the digestive glands, but also the entire vast period of work of the Pavlovian school on the most complex problem of conditioned reflexes.
The long-term development of the physiology of the cerebral hemispheres in the doctrine of conditioned reflexes was the development and completion of the doctrine of the integrity of the organism. The cerebral hemispheres were presented to Pavlov as organs that regulate the relationship of an animal with the outside world in the interests of preserving the integrity of this animal. In experiments with conditioned reflexes, Pavlov paid most attention to the integrity of the organism. Analyzing the complex issue of the inhibitory influences of the external environment on the development of conditioned reflexes in an animal, Pavlov especially emphasized the importance of the integrity of the system.
For Pavlov, the development of an operative-surgical method of research was, in his words, "a method of physiological thinking." It was thanks to this method of physiological thinking that Pavlov managed at the end of the 19th and at the beginning of the 20th century to become one of the few representatives of the holistic study of physiological processes in the era of the heyday of the analytical method of physiology. And it is no coincidence, therefore, that he connected the fate of synthetic physiology with the development of methods for the integral study of physiological processes.
So, Pavlov presented in his work a vivid example of the application of experimental research of life phenomena, created new paths in this direction and put into the hands of physiologists a method for the integral study of physiological processes. But this does not exhaust the characterization of Pavlov as an experimenter. Its most important feature is that it linked the paths of theoretical analysis of the issue with direct practice; he linked questions of physiology with questions of medicine.
Convinced of the great importance of the experiment for the study of processes in a normal organism, Pavlov became a true preacher of the experimental method in the field of medicine. “Only after passing through the fire of experiment, all medicine will become what it should be, i.e., conscious, and therefore always and fully expediently acting ... And therefore I dare to predict that the progress of medicine in one country or another, in one or another another scientific or educational medical institution will be measured by the attention, the care with which the experimental department of medicine is surrounded there. And it is no coincidence that Pavlov's laboratory became a true Mecca for the most advanced representatives of medical science who went to this laboratory to do their dissertations. From the number of Pavlov's students grew leading workers not only in the field of theoretical physiology, but also in the field of the clinic. And his dream is to create an experimental base for medicine in order to provide better conditions“The passionate desire of people for health and life” (Pavlov) has become a reality in our days with the creation of the gigantic All-Union Institute of Experimental Medicine, one of the active figures of which was until his death Pavlov.
Pavlov's understanding of the relationship between physiological theory and clinical practice is characterized by the organic connection of these two scientific lines as mutually fertilizing lines. Not only the physiological experiment and the conclusions from it are the basis for understanding the pathological process and the impact on it, but the pathological process, for its part, is the basis for understanding the physiological processes. The coming to the experimental theory from the physiological experiment in Pavlov is a natural act.
For Pavlov, the pathological process and the normal process are not broken phenomena, but phenomena of the same order.
Throughout Pavlov's entire scientific activity, observations not only on normal animals, but also on sick animals and humans served as an inexhaustible source for his strictly scientific constructions in the field of physiology. First, over random patients, then systematically in hospitals, Pavlov conducted observations as consistently and stubbornly as he did in the physiological laboratory. Clinical cases served him as an indication and impetus for the development of such methods for studying physiological processes in a normal organism, which later became classical. We have in mind the fact that Pavlov discovered the method of imaginary feeding, which he was prompted by clinical cases of patients with an overgrown esophagus.
Pavlov, together with his colleague Shumova-Simonovskaya, gave a method of imaginary feeding, which made it possible to show the fact of the separation activity of the gastric glands under the influence of the nervous system without contact with food, a method that has become a classic. It grew out of the experience accumulated by the clinic.
Having received at the beginning of the XX century. Nobel Prize for classical work in the field of digestion, I. P. Pavlov launched a new cycle of research, organically connected with the first cycle and brought him even greater fame as a great researcher and world scientist. We mean his brilliant work in the field of conditioned reflexes.
The theory of conditioned reflexes as a biological theory was first formulated by Pavlov, and it was precisely as such that it was completed in latest research Pavlov in the field of genetic analysis of conditioned reflex activity. For Pavlov, the development of a conditioned reflex is, first of all, a biological act that creates the prerequisites for the correct exchange of substances and energy between the organism and the external environment. He came to this on the basis of his classical studies on the physiology of the digestive process, the process of perception and processing of nutrients from the outside, as well as on the basis of his, also classical, works in elucidating the trophic role of the nervous system.
Numerous experimental data showed Pavlov the enormous role played by the nervous system in the main biological process - the process of metabolism. He and his students, more than anyone else, were able to convincingly show that in the acts of perception and processing of food, in the acts of obtaining it, as well as in the subtlest acts of chemical transformations of these nutrients in the cells of a multicellular organism, the nervous system plays a leading role. . The doctrine formulated by Pavlov about the trophic role of the nervous system is now being developed into an extremely important branch of physiology.
Pavlov's brilliant discovery lies in the fact that this process of continuous exchange of matter and energy between the organism and the external environment is not only carried out by a complex of innate neuro-reflex acts, but that in the individual development of the animal in each specific case, in each specific situation, new, acquired , environmentally conditioned neural connections (conditioned reflexes), which make the most optimal relationship between animals and the external environment under given conditions. In his speech “Natural Science and the Brain,” Pavlov very clearly defines this biological significance of the conditioned reflexes he discovered:
“The most essential connection of an animal organism with the surrounding nature is a connection through known chemical substances, which must constantly enter the composition of a given organism, that is, a connection through food. On the lower levels of the animal world, only the direct contact of food with the animal organism or, conversely, the organism with food most importantly leads to food metabolism. At higher levels, these relationships become more numerous and more distant. Now smells, sounds and pictures direct animals, already in wide areas of the surrounding world, to the food substance. And at the highest level, the sounds of speech and signs of writing to the press scatter the human mass over the entire surface of the globe in search of daily bread. Thus, countless, diverse and distant external agents are, as it were, signals of the food substance, direct higher animals to capture it, move them to establish a food connection with the outside world.
More than thirty years of work by Pavlov and his students clearly showed that, in addition to innate reflexes based on the anatomical connection of the central nervous system and its conductors with peripheral organs (muscles, glands), there are additional reflexes that can arise during the individual life of an animal in as a result of the coincidence of the action of various, previously indifferent, stimuli of the external world with such stimuli that are unconditional causative agents of one or another reaction (secretory, motor, etc.). This is also the main theoretical prerequisite for the development of methodological techniques, which underlies the Pavlovian technique of conditioned reflexes, in which such indifferent stimuli of the food reaction as light, sound, tingling, etc., become conditioned stimuli of the digestive glands if they coincide with the action unconditioned food irritant - the food itself. From a general biological point of view, experiments with newborn animals carried out in Pavlov's laboratory are especially valuable, in which it was possible to show that if newborn puppies are raised on food devoid of meat (milk-bread regimen), then the look and smell of meat are not causative agents of the digestive glands named puppies. But already after a single giving of meat to puppies, in the future, the look and smell of meat become powerful pathogens, for example, the salivary gland. All this led Pavlov to the conclusion that the animal organism has two types of reflexes: permanent, or innate, and temporary, or acquired.
The sum of the facts obtained in relation to the characterization of the functions of the cells of the cerebral cortex by the method of conditioned reflexes can rightfully be considered the basis for the real physiology of the cerebral hemispheres. These facts provided exceptionally valuable material for understanding the complex problems of the sense organs and their localization; they revealed the physiological nature of the processes of excitation and inhibition in the central nervous system. The very method of salivary conditioned reflexes, in addition to its enormous general biological significance, is essential for the analysis of the question of the nature of the nervous process, especially for the processes of origin and conduction of natural nerve impulses. It can be said without exaggeration that the technique of conditioned reflexes will still provide a great deal for the analysis of complex problems of the reaction of peripheral cells in response to natural stimulation.
The fundamental work of the Pavlovian school on conditioned reflexes is one of the leading chapters in the physiology of the nervous system. It is not superfluous to mention here how this question worried Pavlov. Until recently, he wrote about his indignation at the fact that one of the German physiologists said to prof. Folbort in Kharkov: conditioned reflexes are "not physiology". Deeply affected by this, Pavlov, showing his experiments to our guest Prof. Jordan (Holland), excitedly asked him: "But isn't this physiology?" What prof. Jordanes replied: "Well, of course, this is the true physiology." This is how one of the most prominent representatives of the modern biological direction in the field of physiology answered Pavlov, who sets as his goal the study of the whole organism.
Pavlov tried to comprehend the huge natural-historical experience and observations on the development of conditioned reflexes in the individual life of an animal. As a naturalist, he assessed the importance of conditioned reflexes from a general biological point of view. He said that innate reflexes are species reflexes, while acquired reflexes are individual ones. And further he reported: “We called, so to speak, from a purely practical point of view, the first reflex unconditional, and the second conditional. It is highly probable (and there are already individual factual indications of this) that new emerging reflexes, while maintaining the same conditions of life in a number of successive generations, continuously pass into permanent ones. This would thus be one of the permanent mechanisms for the development of the animal world. And Pavlov returned to this question in his last summary article, written for the Great Medical Encyclopedia in 1935, when he wrote that conditioned reflexes provide everything that is necessary both for the well-being of the organism and for the well-being of the species. In a speech at the International Congress of Physiologists in 1913, Pavlov decisively stated on this occasion: "It can be accepted that some of the newly formed conditioned reflexes later hereditarily turn into unconditioned ones."
Later, under the guidance of Pavlov, Studentsov undertook special studies to test this idea, and Pavlov's speech on the basis of these experiments met with great interest from biologists, because it dealt with such an important issue as the question of the inheritance of acquired traits. This was the subject of special discussion and criticism from geneticists. The prominent American geneticist Morgan spoke out against these experiments and their interpretation, and Pavlov had to agree with the main arguments of the above discussion. But Pavlov not only did not leave the development of the question in this particular biological direction, but developed it further. Here opens a new huge strip of Pavlov's activity in the study of the genetics of higher nervous activity. This new area of research, which formed the basis of the work of the newly created biological station in Koltushi, was to crown the building of Pavlov's thoughts on the biological significance of conditioned reflexes. The very formulation of the question of the genetics of higher nervous activity, the concrete development of the doctrine of the various types of the nervous system in various animals, removed Pavlov's statements cited above about the inheritance of acquired traits as statements not justified by reliable experience.
Pavlov and his students worked out in great detail the typology of the behavior of various dogs, making it the biological basis for setting up experiments on various animals and possible conclusions in each individual case. In a summary article on conditioned reflexes written in 1935, Pavlov points out that “the study of conditioned reflexes in a mass of dogs gradually raised the question of the different nervous systems of individual animals and that, finally, there were grounds for systematizing the nervous systems according to some of their main features. ".
As for the types of the nervous system, on this occasion Pavlov gives an exhaustive description of them, which completely coincides with modern general biological ideas. These thoughts of Pavlov were a truly grandiose plan for a new field of study of the higher nervous activity of animals by the methods of genetics and physiology, which open up an entirely new way of investigating the issue. This time, death placed Pavlov to exhaust the question in the way that he did when creating three new chapters of physiology - digestion, conditioned reflexes, and the trophic role of the nervous system. This work will be the subject of research by a new generation of physiologists.
In the last period of his scientific work, Pavlov exclusively consistently promoted the need for physiologists to study genetics, the application of genetics to the analysis of the types of functioning of the nervous system in animals. This found a symbolic expression in the artistic design that, according to Pavlov's idea, was given to the Koltushi biological station: three sculptures were erected in front of the Pavlovian laboratory in Koltushi - the creator of the concept of the reflex Rene Descartes, the founder of the strictly scientific physiology of the central nervous system Ivan Mikhailovich Sechenov and, finally Gregor Mendel, the founder of modern genetics.
As a deep naturalist, Pavlov showed great interest in the problems of the behavior of animals close to humans, and in last years in his laboratory, research was conducted on monkeys. Constantly interested in the transfer of data obtained in experiments with laboratory animals to humans and specifically raising the question of the features of human physiology, Pavlov was able to come to one of the most profound conclusions regarding human physiology. We have in mind Pavlov's formulation of the question of a special second signal system of reality in the form of a word, peculiar only to man. On this occasion, let us cite an exceptionally bright and concise formulation, which Pavlov gave in his summary article in 1935: “In the developing animal world, an extraordinary increase in the mechanisms of nervous activity took place in the human phase. For an animal, reality is signaled almost exclusively only by stimuli and traces of them in the cerebral hemispheres, which lead directly to special cells of the visual, auditory, and other receptors of the organism. This is what we also have in ourselves as an impression, sensation and representation from the external environment, both general natural and from our social, excluding the word, audible and visible. It is the nervous signaling system of reality that we have in common with animals. But the word constituted our second, special, signal system of reality, being the signal of the first signals.
Special work on questions about the features of human higher nervous activity led Pavlov to the study of human psychopathology, to a psychiatric clinic, where he remained an experimenter who tried to approach the analysis of human mental disorders and treat them on the basis of experimental physiology data.
The new chapter of human physiology discovered by Pavlov about the word as a signaling system began to receive experimental confirmation in the works of Pavlov's school and will be one of the fruitful ways of research, along with the genetics of higher nervous activity, which remained undeveloped in Pavlov's scientific heritage.
Pavlov's doctrine of conditioned reflexes is increasingly gaining citizenship rights outside the Soviet Union and, contrary to the remark of the eminent English physiologist Sherrington that it will not spread abroad, is making its way into a number of countries in Europe and America. This was especially clearly shown by the last International Physiological Congress, at which prof. Sorbonne Luis Lapic declared that the main problems of the physiology of the central nervous system will be solved by applying the method "created by the genius of Pavlov." The doctrine of conditioned reflexes begins to acquire great importance in the analysis of many biological processes, both simple and complex organisms, and this confirms Pavlov's confident view that conditioned reflexes are a process universal for a living system.
The reaction that existed against conditioned reflexes in bourgeois countries, and still partly exists there, rests on deeply fundamental foundations and therefore reveals the tremendous fundamental significance of Pavlov's teaching. Pavlov told how more than 10 years ago, at the anniversary of the Royal Society of London, the famous English physiologist-neurologist Sherington told him: “You know, your conditioned reflexes in England will hardly be successful, because they smell of materialism.” It was to materialism that Pavlov's life as a naturalist was devoted to the end. Observing nature on a “large scale and in general terms”, constantly relying on the “staff of experience”, Pavlov saw before him “a grandiose fact of the development of nature from its original state in the form of nebulae in infinite space to a human being on our planet” (Pavlov) and how the natural scientist did not need to interpret the phenomena of the surrounding nature in forces that lie outside this nature. All the classical heritage of this great researcher and world scientist will be used in building the edifice of strictly scientific, the only correct materialistic knowledge of the world.
The genius researcher of nature, Pavlov, managed with his deep mind to understand that specific historical reality, which he witnessed in his declining years. IP Pavlov was deeply worried about the fate of the culture of mankind, the fate of his homeland. In this sense, he is superior to many of those classics of natural science who, in matters of natural politics, did not rise above the philistine level of their era.
The indisputable merit of the brilliant physiologist Pavlov before mankind will always be that he raised his voice of protest against war and fascism from the rostrum of the world congress. This protest met with a wide response among the outstanding scientists of the whole world, the delegates of the XV International Congress of Physiologists in Leningrad. In the face of militant fascism, Pavlov unconditionally stood up for the defense of his great socialist homeland, leaving behind the memory of a citizen of the USSR, proud of the consciousness of belonging to the great family of peoples of the USSR building a new society. He, an outstanding representative of mental labor, understood and appreciated the historical significance of the Stakhanov movement as a step towards overcoming the contradictions between physical and mental labor. He is an honorary member of many academies and universities of the world, officially recognized at world congresses as "the head of the physiologists of the world" - with great excitement he received the notice of his election by the assembly of Donetsk miners as an "honorary miner".
Dying in the true sense of the word at a scientific post, Pavlov, despite his age (86), was constantly worried about the fate of the Soviet homeland and shortly before his death he wrote his famous message to the youth of the USSR, among whom the image of the great citizen of the USSR Ivan Petrovich Pavlov will always live. .
Ivan Petrovich Pavlov was born on September 14 (26), 1849, in Ryazan. Literacy began when Ivan was eight years old. But he sat down at the school bench only after 3 years. The reason for this delay was a severe injury that he received while laying out apples to dry.
After recovery, Ivan became a student of the theological seminary. He studied well and quickly moved up to tutors, helping his lagging classmates.
As a high school student, Pavlov got acquainted with the works of V. G. Belinsky, N. A. Dobrolyubov, A. I. Herzen, and imbued with their ideas. But the pupil of the theological seminary did not become a fiery revolutionary. Soon Ivan became interested in natural science.
The young man was greatly influenced by the work of I. M. Sechenov, “Reflexes of the brain”.
After graduating from the 6th grade, Ivan realized that he did not want to follow the path he had chosen earlier and began to prepare for entering the university.
Further education
In 1870, Ivan Petrovich moved to St. Petersburg and became a student at the Faculty of Physics and Mathematics. As in the gymnasium, he studied well and received an imperial scholarship.
As he studied, Pavlov became more and more interested in physiology. The final choice was made by him under the influence of Professor I.F. Zion, who lectured at the institute. Pavlov was delighted not only with the art of conducting experiments, but also with the amazing artistry of the teacher.
In 1875 Pavlov graduated with honors from the institute.
Main achievements
In 1876, Ivan Pavlov got a job as an assistant in the laboratory of the Medico-Surgical Academy. For 2 years he conducted research on the physiology of blood circulation.
The works of the young scientist were highly appreciated by S.P. Botkin, who invited him to his place. Accepted as a laboratory assistant, in fact, Pavlov headed the laboratory. During his collaboration with Botkin, he achieved amazing results in the field of studying the physiology of blood circulation and digestion.
Pavlov came up with the idea of introducing a chronic experiment into practice, with the help of which the researcher has the opportunity to study the activity of a healthy organism.
Having developed the method of conditioned reflexes, Ivan Petrovich established that the physiological processes occurring in the cerebral cortex are at the basis of mental activity.
Pavlov's studies of the physiology of GNA had a huge impact on medicine and physiology, as well as on psychology and pedagogy.
Ivan Petrovich Pavlov won the Nobel Prize in 1904.
Death
Ivan Petrovich Pavlov passed away on February 27, 1936, in Leningrad. The cause of death was acute pneumonia. Ivan Petrovich was buried at the Volkovsky cemetery. His death was perceived by the people as a personal loss.
Other biography options
- studying short biography Pavlov Ivan Petrovich, you should know that he was an implacable opponent of the party.
- In his youth, Ivan Pavlov was fond of collecting. At first he collected a collection of butterflies, and then became interested in collecting stamps.
- The outstanding scientist was left-handed. All his life he had poor eyesight. He complained that he "can't see anything without his glasses."
- Pavlov read a lot. He was interested not only in professional, but also in fiction. According to contemporaries, despite the lack of time, Pavlov read each book twice.
- The academician was an avid debater. He masterfully led the discussion, and few could compare with him in this art. At the same time, the scientist did not like it when people quickly agreed with him.
