A blood platelet, round or oval. It is normally found in the blood and in punctates of the lymph nodes and spleen because they have a lot of blood. In the blood smear they have irregular contours, but in the circulating blood they are round or oval.
Size:
2-5 µm.
Cytoplasm:
Has 2 zones:
Hyalomere - homogenous, non-colored, or slightly basophilic base, and
Granulomere - about 15 fine purplish red granules.
Granules are divided into 3 types according to their content:
a-granules – with proteins that take part in clotting (thrombocytic factors, fibrinogen, von Wilebrand factor);
Dense granules – with calcium, phosphates, ADP, ATP, and serotonin; and
Lysosomic granules – with acid phosphatase, b-galoctosidase, b-glycerophosphatase, and other enzymes.
