Platelet

see also Platelet lymphocyte ratio

Platelets, also called “thrombocytes”, are blood cells whose function (along with the coagulation factors) is to stop bleeding.

Platelets have no nucleus: they are fragments of cytoplasm which are derived from the megakaryocytes of the bone marrow, and then enter the circulation. These unactivated platelets are biconvex discoid structures shaped like a lens, 2–3 µm in greatest diameter.

Platelets are found only in mammals, an adaptation that may have evolved to offset the risk of death from hemorrhage at childbirth – a risk unique to mammals.

see platelet count.

see thrombocytopenia.

Mean platelet volume

see Platelet Function.