Methods of physiological research

Evolution of Anatomical Methods

Historically, the study of body functions began with the accumulation of structural data. During the period of empirical knowledge, the foundation was formed by accidental findings from examining wounded soldiers and dissecting animals. In Ancient Egypt, the first, albeit symbolic, knowledge was obtained during mummification when priests extracted internal organs.

A genuine breakthrough was made by Herophilus in Ancient Greece, who was the first to dissect human corpses and systematize the data. However, science later stagnated due to religious prohibitions. The system of Claudius Galen, approved by the church, remained unquestioned for over 14 centuries. In the medieval East, Abu Ali ibn Sina (Avicenna), in his «The Canon of Medicine», summarized anatomical and physiological data while adding his own observations, although researchers often had to secretly steal corpses to do so.

During the Renaissance, Leonardo da Vinci created strikingly accurate anatomical drawings that were hidden from the Inquisition for 300 years. Only Andreas Vesalius, daring to challenge Galen, resumed large-scale human dissections. His work, published in 1543, marked the birth of scientific anatomy.

Later in Russia, N.I. Pirogov introduced the method of anatomical sections on frozen corpses. This approach made it possible to study precise topographical interrelationships between organs without displacing them and was reflected in classical works such as W. Braune's Topographisch-anatomischer Atlas.

The Rise of Experimental Physiology and Surgery

The English physician William Harvey is considered the founder of the experimental approach. In 1628, he published a study in which, using animal experiments, he proved that the heart acts as a pump and blood circulates in a closed loop. This discovery laid the foundation for modern cardiology.

In surgery, the experimental method was solidified by N.I. Pirogov. He insisted that any new operation must be preliminarily justified by animal experiments as well as anatomical and physiological research. Pirogov conducted large-scale experiments: he studied healing processes after cutting the Achilles tendon, investigated the effects of ether vapors, and examined the consequences of ligating the abdominal aorta.

Methods for Studying the Nervous System

To study brain functions, physiologists developed specific approaches combining clinical observation and experiment. For example, observations of the wounded showed that when an attempt was made to extract a shrapnel fragment, a person could suddenly fall asleep, indicating the presence of subcortical sleep centers.

Swiss scientist W. Hess experimentally confirmed this by applying the method of chronic electrode implantation into the subcortical structures of cats. By delivering low-frequency electrical stimulation to the posterior regions of the hypothalamus and subthalamus, he induced immediate sleep in the animals, and upon turning off the current, awakening.

In Russia, I.M. Sechenov investigated the reflex activity of the brain, discovering central inhibition processes and the influence of neurotransmitters on the central nervous system. He proved that consciousness and thinking are not mystical substances. I.P. Pavlov went further, establishing the doctrine of higher nervous activity. In his classical experiments on dogs, he studied the regulation of internal organs and divided all reflexes into unconditioned (innate) and conditioned (acquired).

Study of Individual Variability

Through the efforts of V.N. Shevkunenko and his school, the natural-historical (genetic) research method was developed. It is based on phylogenesis and embryogenesis data, making it possible to identify similarities and differences in the structure of human and animal organs.

To assess the range of variations, anatomical features are arranged in a variational series, where the extreme forms of organ position and structure lie at the poles. This method proved that standard textbook descriptions often do not match the actual picture on the operating table.

Accounting for individual variability in blood vessels, nerves, and internal organs, as well as the correlation of these features with body type, is critically important. This helps physicians diagnose diseases more accurately, understand the course of pathological processes, explain postoperative complications, and choose the most rational surgical approaches. Age-related aspects of organ topography, including in children, were also actively studied by followers of this school, developing the ideas of N.I. Pirogov.

Class and exam questions

What else to study on this topic

• I.M. Sechenov's contribution to the discovery of inhibition processes in the central nervous system
• N.I. Pirogov's experiments with ether vapors and aortic ligation
• The development of I.P. Pavlov's doctrine of higher nervous activity
• The applied significance of individual organ variability in operative surgery
• The history of the development of anatomy from Ancient Egypt to the Renaissance

Other topics in the "Additional Topics" section

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