HUMAN MEDICAL BIOLOGY, ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedonyuk 2010

INTRODUCTION

ANATOMY AND PHYSIOLOGY: SCIENCES STUDYING THE STRUCTURES AND MECHANISMS SUPPORTING HUMAN NEEDS

The Subject of Physiology and Its Relationship with Other Disciplines

Normal physiology is the science of body Functions and the mechanisms of their regulation. A function is The activity of an organ or a system of Organs. A physiological system is defined as a collection of organs that perform a specific function and share common regulatory mechanisms. Regulation refers to controlled changes in activity.

The Theory of physiological regulation is based on THE PRINCIPLE OF nervism—the recognition of The Nervous system's leading role in regulating any bodily function. This regulatory mechanism is called neural or reflex-mediated, with the reflex at its core. A reflex is an Organism's responsive reaction to a stimulus, requiring the mandatory participation of the Central Nervous System. Examples of reflex regulation include withdrawing the hand when pricking a finger or constricting the pupil in response to light.

Another regulatory mechanism is neurohumoral regulation, which is mediated by physiologically active substances transported via the Blood and CEREBROSPINAL FLUID (CSF). For instance, an elevated blood adrenaline concentration increases the force and rate of Heart contractions.

One of the key principles of physiological regulation is self-regulation based on feedback, which operates as a reflex mechanism: the central nervous system receives information regarding whether an organ has completed its work and to what extent. The central nervous system then compares this input with the anticipated, pre-programmed result.

Self-regulation via feedback also plays a vital role in neurohumoral regulation. For example, an increase in blood glucose levels is detected by glucosensors, which signal this change to the central nervous system. This triggers the release of the pancreatic hormone Insulin into the bloodstream, which reduces sugar concentration.

Physiology and medicine are closely interconnected. A physician assesses the severity of a disease based on the degree of functional impairment and the magnitude of deviation of physiological functions from the norm. Furthermore, functional physiological tests (such as electrocardiography, Electroencephalography, blood and urine tests, etc.) form the foundation of clinical Diagnostics, as well as Methods for evaluating Treatment efficacy and disease prognosis. The goal pursued by a physician during patient examination and treatment is to restore functions and their regulatory mechanisms to baseline normal values. Because physiology studies functions and their regulatory mechanisms in a healthy body, it serves as the theoretical foundation of medicine.

The Study of physiology is essential for the scientific substantiation and creation of conditions for a healthy lifestyle aimed at preventing disease. Preserving human health is one of the paramount tasks of modern medicine, and accomplishing this task relies on physiological knowledge. Thus, physiology forms The basis of preventive medicine.

Physiology is closely related to allied sciences: anatomy, Histology, biochemistry, biophysics, cybernetics, and biology as a whole. It widely applies their methods and achievements when studying body functions, relying primarily on disciplines that investigate structural Organization, because Structure and function are dialectically linked. One cannot understand an organ's function without knowing its morphological characteristics.

Physiology is an experimental science. Its core principles are grounded in facts obtained through experimentation. A fundamentally new method for studying physiological processes was created by the eminent physiologist I.P. Pavlov.

For centuries, physiology relied on acute animal experiments. The Essence of an acute experiment is that the integrity of the organism is compromised through vivisection (dissection of a living organism). During this Procedure, the researcher observes either the activity of individual organs in the operated animal or the activity of organs isolated from the body that continue to function under specially created conditions. The animal perishes following an acute experiment. This is an analytical method.

I.P. Pavlov sharply criticized vivisection. He introduced a new method into physiology: the chronic experiment, which is a synthetic research method. A chronic experiment allows physiological processes to be studied without disrupting the integrity of the organism. The essence of this method is that surgical intervention is performed on a anesthetized animal under sterile conditions. For example, a fistula tube is inserted into The Stomach to collect gastric juice and study the mechanisms and REGULATION OF GASTRIC secretory activity. Only after the wound heals and recovery is complete does the operated animal become the subject of long-term observation—sometimes for many years. This takes place under natural behavioral conditions within the intact organism of the animal.

The method proposed by I.P. Pavlov is based on studying physiological processes occurring within an intact organism maintaining normal interaction with the external

environment, making it an analytical-synthetic approach. This is the primary method used in modern physiology.

Physiology also employs the observational method. In this approach, the researcher investigates the cause-and-effect relationships of physiological processes without interfering with the ongoing life processes of the observed subject.

The modeling method is widely used. By utilizing a model functionally similar to a specific organ or organ system (such as an artificial heart or artificial Kidney), researchers study the functions