08 July, 2011
Thrombocytes, or platelets, are the most important cells involved in blood clotting of blood. Platelets help in the clotting of blood by working together with clotting factors produced by the liver. Vitamin K is needed in the activation of several clotting factors. Low platelets and low vitamin K increase the tendency to bleed.
Platelets are cell fragments of bigger cells called megakaryocytes. Platelets are produced by the bone marrow. Platelets contain several compounds that are important for clotting, they include ADP, thromboxane, prostacyclin and growth factors. These compounds are contained in vesicles and are released upon platelets activation.
Platelets float around in blood until they encounter breaks in blood vessel walls; on site, platelets are activated by thrombin, a product of the coagulation cascade which involves a series of reactions between clotting factors. Platelets interact with collagen fibers that are exposed as the result of a break in the blood vessel wall; collagen fibers also facilitate the activation of platelets. Thromboxane and ADP, are other factors that participate in platelet activation.
Thrombocytopenia, or low platelets, is defined as a platelet count less than 150,000 platelets per microliter of blood. The several causes of low platelet counts can be categorized into three main groups: causes that decrease platelet production, causes that increase platelet destruction and abnormal distribution of platelets. Thiazide diuretics, alcohol and leukemia are causes that decrease platelet production. Platelets can be destroyed by an over active immune system, HIV and heparin. A low platelet count may also be caused by increased sequestration of platelets in the spleen.
Green leafy vegetables such as broccoli and Brussels sprouts, are rich sources of vitamin K. In adults, the recommended intake of vitamin K is 80 mg per day for males and 65 mg per day for females. Vitamin K is also produced by bacteria in the gut. Vitamin K deficiency is usually caused by decreased absorption in the gut. Vitamin K deficiency can result from antibiotic use.
- hand with blood image by Ivonne Wierink from Fotolia.com