The internal environment of the body and its meaning

The phrase "internal environment of the body" appeared due to the French physiologist Claude Bernard, who lived in the XIX century. In his works he emphasized that the necessary condition for the life of the organism is the maintenance of constancy in the internal environment. This provision became the basis for the theory of homeostasis, which was formulated later (in 1929) by the scientist Walter Cannon.

Homeostasis is the relative dynamic constancy of the internal environment, As well as some static physiological functions. The internal environment of the body is formed by two liquids - intracellular and extracellular. The fact is that every cell of a living organism performs a certain function, therefore it needs constant supply of nutrients and oxygen. She also feels the need to constantly remove the products of exchange. The necessary components can penetrate through the membrane exclusively in a dissolved state, which is why each cell is washed with a tissue fluid, which has everything necessary for its vital activity in its composition. It refers to the so-called extracellular fluid, and it accounts for 20 percent of body weight.

The internal environment of the body, consisting of extracellular fluid, contains:

• Lymph (a component of the tissue fluid) - 2 liters;
• Blood - 3 liters;
• Interstitial fluid - 10 liters;
• Transcellular fluid - about 1 liter (it includes spinal, pleural, synovial, intraocular fluid).

All of them have different composition and differ in their functional Properties. Moreover, the internal environment of the human body can have a small difference between the consumption of substances and their intake. Because of this, their concentration is constantly fluctuating. For example, the amount of sugar in the blood of an adult can vary from 0.8 to 1.2 g / l. In the event that the blood contains more or less specific components than necessary, this indicates the presence of the disease.

As already noted, the internal environment of the body contains blood as one of the components. It consists of plasma, water, proteins, fats, glucose, urea and mineral salts. Its main location is the blood vessels (capillaries, veins, arteries). Blood is formed due to absorption of proteins, carbohydrates, fats, water. Its main function is the interrelation of organs with the external environment, the delivery to the organs of the necessary substances, the excretion of the decay products from the body. It also performs protective and humoral functions.

Tissue fluid consists of water and nutrients dissolved in it, CO ₂ , O ₂ , and also from products of dissimilation. It is in between the cells of tissues and is formed by the blood plasma. Tissue fluid is intermediate between blood and cells. It transfers from blood to O ₂ cells, mineral salts, nutrients.

Lymph consists of water and organic substances dissolved in it . It is in the lymphatic system, which consists of lymphatic capillaries, vessels drained into two ducts and flowing into the hollow veins. It is formed at the expense of tissue fluid, in pouches that are located at the ends of the lymphatic capillaries. The main function of lymph is the return of tissue fluid to the bloodstream. In addition, it filters and disinfects the tissue fluid.

As we see, the internal environment of the body is a combination of physiological, physico-chemical, respectively, and genetic conditions that affect the viability of a living being.