Blood is a biological fluid, constantlycirculating in the circulatory system, containing nutrients and gases. Thanks to her metabolism takes place in the body, tissues and organs receive everything necessary for their life and give the products of metabolism. It consists of cells, called shaped elements, and plasma. Formal blood elements make up just over 40% of the blood volume, the rest of it is in the liquid part of the blood - plasma. Blood in the body performs a number of important functions - nourishing, respiratory, protective, heat exchange.
All blood elements are divided intothree large groups of cells - erythrocytes, leukocytes and platelets. The bulk of cells are red blood cells, sometimes called red blood cells. It is the red blood cells that give the blood a red color. The main function of erythrocytes is to perform gas exchange, that is, to transport oxygen to the cells of the body and take away carbon dioxide from them. To perform gas exchange, red blood cells contain a special protein called hemoglobin. In form, red blood cells are similar to discs concave from both sides. Due to this form they can easily penetrate into the smallest capillaries. In addition, the concavity on both sides makes it possible to increase the surface of the erythrocytes, which is necessary for better transport of oxygen. Erythrocytes do not have nuclei. The lifespan of these cells is from 90 to 120 days, normal in men, a liter of blood on average contains 5x10 in the 12th degree, and in women - 4.5x10 in the 12th degree of erythrocytes.
The next variety of blood cells -leukocytes, that is white blood cells. These uniform elements play an important role in protecting the body from pathogens, viruses, various foreign substances. They purify the focus of infection after the destruction of bacteria, produce antibodies that play an important role in the formation of immunity. Leukocytes are formed in the bone marrow, spleen, lymph nodes. These are colorless cells with well developed nuclei. The content of leukocytes in human blood is 4-10 × 10 in the ninth degree per liter of blood.
Depending on the presence of granularity in the cytoplasmleukocytes are divided into granulocytes and agranulocytes. Granulocytes include eosinophils, basophils and neutrophils, agranulocytes include lymphocytes and monocytes. Each of the forms of leukocytes has its own specialization, it is responsible for performing various kinds of functions.
Formed elements of blood called platelets,in fact, are fragments of large cells - megakaryocytes. Platelets are also called blood plates. Like leukocytes, they are colorless, contain no nuclei, have an irregular shape. Platelets are extremely variable, rapidly destroyed in fresh preparations. Blood plates play a crucial role in the processes of folding, formation of blood clots and stopping bleeding. The number of platelets in the blood ranges from 200 to 400x10 in 9 degrees per liter of blood.
Formal elements of blood are formed inhemopoietic organs, which are the bone marrow, lymph nodes, spleen. In the body there is an inseparable connection of the shaped elements with the organs in which they are developed and destroyed and the apparatus of regulation of this process.
The content of different kinds of shaped elements -the value is relatively constant. Abnormalities can be an important symptom of various diseases. The number of different types of blood cells reflects a detailed general blood test with a leukocyte formula. This analysis includes the amount of hemoglobin, color index, ESR, blood elements. The analysis table reflects all these indicators in the norm, with which you can compare the results obtained.
