Platelets are produced in the bone marrow by highly specialized cells called megakaryocytes. About 70–80% of a person's total platelet count circulates in the vasculature at any time. The other 20–30% are pooled in the spleen.
The average lifespan of a platelet is 9–12 days.
Platelets play a significant role in primary hemostasis. They are the “bricks” or building blocks of the developing platelet plug, the forerunner to the end-stage fibrin clot. Platelets have inherent adhesive properties, essential for adherence to the site of vascular damage and binding to one another in aggregation activities.
Platelets must be in sufficient numbers and functionally active for optimal clotting. However, platelet functionality tends to be more crucial than the number of platelets available, as patients with lower platelet counts can still clot relatively effectively compared to those with intrinsic platelet defects.
