phrase "internal environment" appeared thanks to the French physiologist Claude Bernard, who lived in the XIX century.In his works he emphasized the fact that a necessary condition for the life of the body is to maintain the constancy of the internal environment.This provision became the basis for the theory of homeostasis, which was formulated later (in 1929), scientist Walter Cannon.
Homeostasis - 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 that each cell of a living organism has a specific function, so it needs a continuous supply of nutrients and oxygen.She also feels the need for constant removal of metabolic products.Necessary components can penetrate through the membrane only in the dissolved state, which is why every cell is washed by interstitial fluid, which incorporates everything necessary for its functioning.It belongs to the so-called extracellular fluid, and it accounts for 20 percent of body weight.
internal environment, consisting of the extracellular fluid contains:
- lymph (a part of tissue fluid) - 2 liters;
- blood - 3 l;
- interstitial fluid - 10 liters;
- transcellular fluid - about 1 liter (it is composed of cerebrospinal, pleural, synovial, intraocular fluid).
All have different composition and differ in their functional properties.Moreover, the internal environment of the human body may be a slight difference between the consumption of substances and their revenues.Because of this concentration is constantly fluctuating.For example, the amount of sugar in the blood of adult human may range from 0.8 to 1.2 g / l.In that case, if the blood contains more or less defined components than necessary, this indicates the presence of disease.
As already noted, the internal environment of the body as one of the components contains blood.It consists of plasma, water, protein, fat, glucose, urea and mineral salts.Its main location is the blood vessels (capillaries, veins, arteries).To form the blood due to the absorption of proteins, carbohydrates, fats, water.Its main function is the relationship of the external environment, delivery to the organs necessary substances, removal of decay products from the body.It also has a protective function and humoral.
Tissue fluid consists of water and dissolved nutrients, CO2, O2, as well as products of dissimilation.It is in the interstices between cells and tissues is formed by plasma.Tissue fluid is intermediate between the blood and cells.It suffers from the blood into the cells of O2, minerals, nutrients.
Lymph consists of water and dissolved organic matter.It is located in the lymphatic system, which consists of the lymph capillaries, blood vessels, fused to the two duct and empties into the vena cava.Formed by the tissue fluid in the pouches, which are at the ends of the lymphatic capillaries.The main function of the lymph tissue fluid is returned to the bloodstream.In addition, it is filtered and disinfects the tissue fluid.
As we can see, the internal environment of the body is a combination of physiological, physical and chemical, respectively, and genetic conditions that affect the viability of a living creature.
