What is a platelet? What is their role in the body? At what diseases platelets are increased

Platelets are small, non-nuclear shaped elements of blood. They participate in hemostasis (a complex of reactions aimed at stopping and preventing bleeding). The platelets are round or oval in shape. The diameter of the cells is from two to four microns.

In blood vessels, platelets are located at the walls or in the bloodstream. In the second case, the cells are in a calm state and have a disk shape. Activation of platelets contributes to a change in their shape: the cells become spherical and form special outgrowths (pseudopodia). With the help of these processes, the blood cells are able to adhere to each other or to the wall of the vessel that is damaged. This phenomenon is called aggregation (coalescence). Platelets also have properties for adhesion (adhesion), degranulation (release of contents), clot retraction (complete separation or reduction of blood clots from serum). On their surface, these cells are able to tolerate fibrinogen, substances that are active biologically (serotonin), anticoagulants, and immune complexes (circulating).

By adhesion and aggregation of platelets , hemostasis is provided in small-calibrated vessels (cells accumulate in the site of injury). Adrenaline, thrombin, collagen, serotonin act as stimulants of the adhesion process. With the participation of thrombin, shoots (pseudopodia) form. Granules of platelets contain clotting factors (serotonin, peroxidase enzyme, platelet fibrinogen, adenosine diphosphate (ADP), serotonin, platelet growth factor, von Willebrand factor).

During the retraction of the blood clot, adherence to the filaments of fibrin and release of thrombostenin, which settles on them, occurs. As a result, the threads are compressed and twisted, thus a primary thrombus is formed.

A blood test for platelets allows you to determine the clotting factor. Normal concentration is 180-320 thousand per one milliliter.

If the platelets are elevated, then there is thrombocytosis. This condition can indicate chronic diseases of infectious nature, tumors, blood diseases. Thrombocytosis can cause the formation of blood clots in blood vessels. If the platelets are raised, then the body may be dehydrated. Such a condition can be triggered by vomiting, insufficient fluid intake, stool disorder.

The concentration of platelets in the blood can vary depending on the time of year or day. The decrease in the content of cells can occur during the menstrual period or during pregnancy. Often platelets are elevated after physical stress.

Thrombocytosis can occur in both adults and children. Increase in the concentration of platelets can be primary or secondary.

In children, thrombocytosis is established after exclusion of congenital pathologies.

The platelets are usually increased, as a rule, with erythremia, chronic myelogenous leukemia and other blood diseases. An increase in the concentration of blood bodies is associated with the acceleration of the division of their precursor (megakaryocytes). This process is typical for tumor transformation.

Secondary thrombocytosis is detected in diseases that have arisen on the basis of increased production of thrombopoietin (polypeptide hormone).

Platelets raised may be with ulcerative colitis, pulmonary tuberculosis, joint damage of rheumatoid nature, extrapulmonary tuberculosis, amyloidosis, osteomyelitis, liver cirrhosis and other chronic inflammatory pathologies. Thrombocytosis occurs against the background of the development of malignant neoplasms, bleeding, after certain birth injuries.