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Thrombocytes represent small colourless little bodies of a flat dvoyakovygnuty form which circulate in blood in a large number. They are the post-cellular structures surrounded membry. The place of formation of thrombocytes – red marrow. Their average life expectancy fluctuates in an interval from 2 to 10 days then there is a utilization of thrombocytes reticuloendothelial cells of a spleen and liver.
On degree of a maturity distinguish 5 forms of thrombocytes: young, their specific weight the most minimum – to 1%, mature of which the majority of thrombocytes in blood – from 90 to 95% are the share, old, thrombocytes of a form of irritation and degenerative forms.
Main properties of thrombocytes
The main function of thrombocytes consists in prevention of a loss of blood in case of wound of vessels. This function is carried out in several stages: adhesion, secretion, retraction, vasospasm, formation of white blood clot. Thus, the thrombocyte is the major cell which is responsible for coagulability of blood. Their shortage can result, except deterioration in coagulability of blood, in fragility of vessels, they become less elastic that conceals in itself big danger. Besides, deterioration in coagulability of blood can not prove in any way the whole years therefore it is very important to make blood test regularly. Bad coagulability of blood can lead to the fact that even the smallest wound does not heal, without speaking already about danger of internal bleedings and healing of fabrics after an operational smeshatelstvo.
Not so long ago also the fact that thrombocytes are essential in regeneration and healing of the damaged fabrics was determined. They release from themselves growth factors in wounded fabrics which provide stimulation of growth and division of the damaged cells. Such growth factors are polypeptide molecules of different function and structures. The major growth factor are the platelet growth factor, a growth factor of an endothelium of vessels, a transforming factor of growth, an epithelium growth factor, an insulinopodobny growth factor and a growth factor of a fibroplast. Except above-mentioned functions thrombocytes carry out food of an endothelium of blood vessels at the expense of what angiotrofichesky function is provided. Also they allocate and make a set of biologically active agents: noradrenaline, serotonin, adrenaline, etc.
The lowered and increased concentration
When the level of thrombocytes in blood becomes lower in 100 × 10 marks 9/l is already alarming sign for the patient. This state is called thrombocytopenia. It can develop at a hypothyroidism, a thyrotoxicosis, the increased utilization and (or) destruction of thrombocytes, accumulation of thrombocytes in a spleen, reduction of formation of megacaryocytes, influence of drugs which suppress work of marrow, megaloblastny anemias, preleykemichesky a syndrome, alcoholism, etc. Level of thrombocytes can also decrease as a result of chemotherapy, because of influence of metabolites of a lymphoma on marrow. Besides, decrease in their concentration can arise because of change of properties of lymphocytes.
The condition of the increased concentration of thrombocytes in blood is called a thrombocytosis. Quite often it develops against such diseases and pathological processes as hemorrhages, chronic inflammatory processes, growth of malignancies, acute infections, oncological diseases of blood, hemolysis, etc.
The main sign of decrease in level of thrombocytes is – the raised bleeding. It is shown in the form of red-violet bruises and points, bleeding of gums and a mucous membrane of a nose, menstrual and intestinal bleedings can also develop. Such disturbances are a good motive for the address to the specialist who without fail has to appoint to the patient blood test.
Norm of thrombocytes
The norm of thrombocytes in blood for adult women and men makes 180-320×10 9. It can vary a little at high exercise stresses, and also depending on a season and time of day.