What Is Tissue Homeostasis?

Homeostasis refers to the physiologist's adjustment of the normal body to coordinate the activities of various organs and systems to jointly maintain a relatively stable state of the internal environment. The relative stability of the internal environment is a condition for the free survival of organisms.

Physiology refers to the state where the physicochemical properties of extracellular fluid remain relatively stable, called homeostasis. Its physical and chemical characteristics, including temperature, osmotic pressure, pH, and various ion concentrations, must always be relatively stable. Homeostasis is a dynamic process because life activities are undergoing metabolism at all times. The oxygen and nutrients needed for life activities are obtained from the environment through the respiratory and digestive systems; at the same time, the metabolic waste generated during the metabolism process must be Excreted by excretory organs; so change is absolute, while unchanged is relative. The maintenance of the internal environment is a complex physiological process, such as: gas exchange in the respiratory system, food intake, digestion and absorption by the digestive system, kidney urine generation and discharge, cardiovascular pumping function and blood transport The regulation of the nervous system, etc., keeps the physical and chemical characteristics of the internal environment relatively stable. If the amplitude of the changes in the physical and chemical characteristics of the internal environment is too large, exceeding the regulation limit of the human body will lead to disturbances in human physiological functions. In the 19th century French Open physiologist Claude bemard put forward the concept of the internal environment, saying that the relatively stable internal environment is a condition for the free survival of organisms. ^[1]

For humans and higher animals, homeostasis is a necessary condition for cells to maintain normal physiological functions and even for the body to maintain normal life activities. The steady state of inner ring culture means that under normal circumstances, the various components and physical and chemical properties of the internal environment of the body only change within a small range. For example, body temperature is maintained at about 37 ° C, plasma pH is maintained at about 7.4, arterial blood pressure, partial pressure of oxygen and carbon dioxide in plasma, and glucose concentration are also maintained at relatively constant levels.

Various metabolic activities of cells are enzymatic biochemical reactions. Therefore, there must be sufficient nutrients, oxygen and water in the internal environment, as well as appropriate temperature, ion concentration, pH and osmotic pressure. Certain ion concentrations and distributions on both sides of the cell membrane are necessary conditions for certain cells to maintain their normal excitability and normal bioelectric activity. The destruction of the internal environment's homeostasis will affect the normal progress of cell life activities, such as high fever, acidosis, hypoxia, and changes in ion concentration, etc. will cause severe disturbance of cell function, cause disease, and even endanger life.

The homeostasis is a dynamic equilibrium. Cell metabolism will continuously consume O ₂ and nutrients, and at the same time continue to produce metabolites such as CO ₂ and H ⁺ . Changes in external environmental factors can also affect the homeostasis of the body, but the body can make use of the activities of multiple organs and systems The internal environment remains relatively stable. For example, O ₂ and nutrients required for metabolism can enter the body from the respiratory and digestive systems, while CO ₂ and H ⁺ produced by metabolism are excreted through the respiratory and urinary systems. These substances are transported through the blood circulation system, and the functions of various organs and tissue cells remain relatively stable under the regulation of the nervous and endocrine systems. ^[2]

Hundreds of millions of cells make up human and animal bodies, and most of them cannot directly contact the external environment. So, in what kind of environment do these in vivo cells isolated from the external environment live? How they interact with the environment

With the development of cybernetics and other life sciences, homeostasis not only refers to the stable state of the internal environment, but also extends to a large number of coordinated and stable physiological processes in the organism, such as life activity functions and normal postures (upright and road postures) ) Maintenance, etc .; also used at different levels or levels of the body (cells, tissues, organs, systems, the whole, social groups) stable state; and a specific state maintained for a specific time (from a few milliseconds to tens of thousands of years). Homeostasis is not only a physiology, but also a fundamental concept in life sciences today. It is of great significance to a variety of disciplines such as cybernetics, genetics (steady regulation of genes), psychology (emotional stability, etc.), pathology, and clinical medicine.

Systems related to the homeostasis: digestive system, respiratory system, urinary system, and circulatory system.