the BLOOD circulates in the circulatory system of all vertebrates and some invertebrates. It provides the vital functions of the body.
in humans, the normal blood volume is on average 4 - 5 liters, with part of it sometimes can be in so-called depot blood - up to 50%.
the Blood performs the following functions:
- breathing, carrying out the transport of gases (oxygen from the respiratory organs to tissues and carbon dioxide from the tissues to respiratory organs);
- trophic and excretory, transferring nutrients from the digestive organs to the tissues and end products of metabolism from the tissues to the excretory organs;
- regulatory, participating in humoral regulation (transfer of hormones and other biologically active substances), maintaining water-salt metabolism and acid-base balance, performing an important role in maintaining a constant body temperature;
- protective, absorbing and destroying foreign agents.
in humans, as in animals, blood consists of liquid portion (plasma) and formed elements (erythrocytes, leukocytes, and platelets).
red blood cells
red blood cells got its name from the Greek word erythros, which means red. This color gives them a special protein - hemoglobin, it can be transferred to the oxygen and carbon dioxide. In the blood vessels of the lungs to haemoglobin in the red blood cells with oxygen molecules, they are delivered to every cell of our body. In the tissues of the process of liberation of oxygen to hemoglobin is released to join the molecules of carbon dioxide. Along with the blood red blood cells again, into the lungs, where carbon dioxide is released through respiration is excreted from the body.
Erythrocytes are involved in the regulation of acid-base balance, they adsorb from plasma amino acids and lipids and carry them to tissues.
The diameter of the erythrocyte of man is equal to 7 - 8 microns. On the surface of red blood cells are antigens specific (factors blood), which determine the group affiliation of the blood.
Red blood cells are constantly being destroyed and formed again, however, their total number in the norm remains constant (about 4 million in 1 ml of blood). The average life of a red blood cell is 120 days. The function of the natural replenishment of red blood cells belongs to the marrow. In the human body every second produces about 2.5 million new red blood cells. Under the influence of any factor leading to the lack of oxygen in the tissues, the rate of formation of red blood cells increases.
the white blood cells got its name from the Greek word leukos - white. Leukocytes vary in appearance and function, but overall they perform protective functions. Leukocytes are constantly on guard. As soon as the human body gets an infection - they come in.
Some white blood cells (lymphocytes) can produce protective proteins (antibodies) that neutralize or destroy viruses and bacteria.
In one milliliter of blood of a healthy person contains from 4 to 8 thousand white blood cells. Like erythrocytes, leukocytes are formed from hematopoietic stem cells, but their life cycle is comparatively short - from several days to several weeks.
Too large or too small number of leukocytes in the blood may indicate the presence of serious diseases.
the Platelets not in vain got its name from the Greek word thrombos - clot, because they play an important role in blood clotting. It is a colorless, non-nuclear corpuscles with a diameter of 2 - 5 microns. In 1 milliliter of blood of an adult person contains 180 - 320 thousand platelets. They are formed in the hematopoietic organs megakaryocytes by separating the plots of their cytoplasm. The lifespan of platelets is not great - 8 - 11 days.
Plasma, the liquid part of blood, is a transparent liquid straw-yellow color on 90% consists of water. This is an extremely important component of blood. About 1% of the plasma volume amount of dissolved salts of calcium, potassium, phosphoric acid, sodium and about 7% proteins. In blood plasma is fibrinogen involved in blood coagulation, glucose, and other nutrients and waste products.
the Constancy of the blood is provided by a state of dynamic equilibrium processes of hematopoiesis and roversrawsome.
Hematopoiesis is the formation, development and maturation of blood cells in the human body. This is a genetically determined multi-step process.
In adults, red blood cells, platelets and part of the white blood cells formed in the red bone marrow. The remaining part of the white blood cells formed in the thymus (T-lymphocytes) in the bone marrow (B-lymphocytes) in the spleen, lymph UZлах, lymphoid follicles in the course of the digestive and respiratory tracts.
The initial form of all blood cells - pluripotential hematopoietic stem cell capable of self-maintenance and differentiation into Mature blood cells throughout a person's life.
the blood Service collects blood from voluntary donors to save the lives of patients needing blood transfusion.
Currently, whole blood is not used. Each unit of blood is separated into components. The patient receives only the component he needed. Thus, the blood of one donor saving the lives of several people.
Preparations made from donated blood are used in complex operations, delivery of babies, treating patients with bleeding, severe trauma, anemia, leukemia, cancer, liver disease and many other occasions.
the Only source of blood is a donor and cannot be replaced.
blood donations needed daily and each croudace will save someone's life.
Come give blood and save the lives of many people, they need Your help!