I. P. Pavlov is one of the founders of the physiology of the digestive system. One of the most valuable merits of the physiologist is the creation of the foundation for further scientific research on the digestive tract. The physiologist, who was later awarded the Nobel Prize, applied the most innovative methods. A high level of skill was already evident in Pavlov's first studies.
Discoveries in physiology and psychology
Pavlov's method, with which the physiologist performed his famous experiments with dogs, is known to every schoolchild. Thanks to his most famous experiments, the scientist was able not only to study the composition of digestive juices, which laid the foundations of modern physiology, but also to draw important conclusions regarding the functioning of the central nervous system. That is why Pavlov's method in psychology is no less important than in the field of physiology and medicine. Based on the concept of a conditioned reflex he discovered, the scientist was able to explain the most complex processes that take place in the human cerebral cortex.
Pavlov was a follower of Sechenov. However, when the latter had to leave Petersburg, the great Russian physiologist continued his studies withI. F. Ziona, who taught him the virtuoso technique of operations. Pavlov devoted more than a decade to being able to install fistulas (or holes) in the walls of the esophagus of animals.
Beginning with the study of the salivary glands, Pavlov had the best research base of all the questions of physiology in which he de alt. However, the theoretical conclusions of that time contained many erroneous provisions. For example, it was believed that reflex salivation depends entirely on the excitation of receptors located in the oral cavity. Pavlov's method, which was called a chronic experiment (such when the animal remained alive after the experiments). He made it possible to advance the physiology and medicine of that time to a significant level.
Innovative way
In order to be able to study the composition and action of digestive juices, they had to be somehow obtained in their pure form. Obtaining gastric juice by Pavlov's method has become one of the most advanced and progressive steps in research on the physiology of internal organs. Not a single physiologist could do this before IP Pavlov. For example, the following operation was often used: the dog's gastric cavity was opened and the pancreatic duct was found. A tube was inserted into it, and in a few minutes, while the animal was still alive, the researchers received just a few drops of gastric juice. Pavlov was against such operations, since the material obtained by this method was contaminated. This datacould not advance medical science in any way.
Features of the physiologist's experiments
Pavlov's method was fundamentally different from the attempts of his predecessors to obtain material for research. Having found the pancreatic duct, the scientist separated it from the duodenum. Then he sewed a piece of the intestinal wall to the edges of the wound on the surface of the abdomen. Now the gastric juice was produced outside - in a specially substituted funnel.
If the animal had he althy other glands, this did not affect its life in any way - for several years the dogs were completely he althy and fit for experiments. The obvious advantage of all Pavlov's research methods was the ability to save the life and he alth of the experimental animal. IP Pavlov was aware of the general property of life - for the most part, in all living organisms there is redundancy, the same function is provided in different ways, and because of this, the organism almost always has reserve opportunities for survival.
Merit of a scientist
Pavlov installed permanent fistulas in animals. With their help, it was possible to constantly monitor the activity of a particular internal gland. For the method of Pavlov was called fistula. With this method, the physiologist was able to collect the digestive juices produced in various phases of the food processing process. The role of the physiologist in the study of the activity of the digestive glands cannot be overestimated - this sectionphysiology, scientists are often called the "Russian head", and I. P. Pavlov himself in 1904 was awarded the highest award - the Nobel Prize.
Another discovery
Pavlov's method also made it possible to study the formation of conditioned and unconditioned reflexes. Pavlov noticed that the dog's gastric juice is secreted not only at the sight of food, but also when the animal hears the noise of the steps of the person who brings it. So the scientist began to study the processes of vital activity of the brain. Moreover, reactions of this kind could be developed in animals not only in response to the noise of steps, but also to turning on the light, ringing a bell, various smells, etc.
Types of reflexes
The physiologist divided all the possible responses of the body into two categories. He called innate reactions unconditional, and those that were acquired in the process of life - conditional. The first category includes protection from enemies, searching for food, as well as quite complex actions - for example, building a nest. Unconditioned reflexes are inherent in every living organism from birth. And the execution of those commands that the animal receives from the trainer belongs to the category of conditioned reflexes.
They can exist for quite a long time, but sooner or later they can disappear, slow down. At the same time, the physiologist found out that the process of inhibition can be external. For example, a dog has already developed a salivary reflex to turn on the light. If, however, the switching on of the light bulb is accompanied by an unusual noise for the animal,then the conditioned reflex in some cases may not appear. It was for this reason that a special department was built at the institute where Pavlov conducted his experiments - the "Tower of Silence", in which the walls were very thick and did not let in extraneous sounds.
Signal systems
The researcher singled out two signal systems that are inherent not only in animals, but also in humans. People, as well as animals, perceive signals from the outside world. This type of physiologist called the first signaling system. However, a person differs significantly from his smaller brothers in the socially conditioned second signal system - speech. Without communication with other people, this type of system does not develop in a person. The research methods of I. P. Pavlov are widely recognized not only in physiology and medicine, but also in psychology and pedagogy.
Research
For example, Pavlov managed to draw an important conclusion: the secretion of salivation is not always the same. This process varies and is influenced by several factors: firstly, it is the strength, nature, and also the number of external stimuli; and secondly, the direct functional significance of the saliva produced (it can be digestive, hygienic or protective). After analyzing the results obtained during the experiments, Pavlov made the most important conclusion: the subtle variability in the work of the salivary glands is dictated by the different excitability of the receptors located in the oral cavity to various stimuli. These changes are adaptive. Later, the physiologistfound that this conclusion is also valid for another type of saliva - mental secretion.
Merit of a physiologist
Pavlov's work methods are rightfully called advanced for another reason: one of the most important merits of a physiologist is the discovery of the leading role of the nervous system in a living organism. It is the nervous system that plays a primary role in the work of various digestive glands, the regulation of the work of other internal organs. This doctrine was later called nervism. The knowledge gained by Pavlov is also used in the modern world. It is on the basis of this information that various medicines are used to treat the digestive system, and recommendations are given regarding proper nutrition.
For the first time, the scientist voiced his research in the field of physiology of higher nervous activity at the Madrid report, written in Russian. In total, the scientist devoted a total of about 35 years to studying the physiology of the nervous system.
Obtaining clean material
What method did Pavlov use to determine the composition of pure gastric juice? If we talk about terminology, then his method got its name - "method of imaginary feeding." It became possible to study pure gastric juice only after the application of this experiment by I. P. Pavlov and E. O. Shumova-Simanovskaya. It was first held in 1889. Another operation was added to the fistula - transection of the esophagus. However, the esophagus was not cut completely. Only two-thirds of its thickness was subject to dissection - the edges were sewn to the surfaceneck muscles.
Science and animal life
A huge number of disputes about their ethics still cause Pavlov's method. Dogs at the same time aroused admiration from the great physiologist. Pavlov considered them perfect animals and sincerely mourned every life that had to be put on the altar of scientific research. The scientist tried to minimize the suffering of experimental animals. He only resorted to putting them to sleep when they no longer had a chance.
