Library · Physiology
Platelet function
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Platelets are disc-shaped cells that have no nucleus. They arise from megakaryocytes, very large cells in the bone marrow, which is the tissue inside the bones where blood is made.
When a vessel breaks, several things happen one after another. First the vessel contracts, which is called vascular spasm and causes vasoconstriction, meaning the vessel narrows. When the inner lining tears, the collagen of the extracellular matrix, the supporting mesh that lies underneath, is left exposed. That is where von Willebrand factor comes in, a protein that works like glue and ties the platelet to that surface.
The platelets that have attached then release their granules, internal packets that carry ADP, thromboxane A2 and serotonin. They also stick to one another, which is called aggregation, and form a temporary platelet plug. A plug built right in the hole, out of the body's own cells.
In brief
Platelets are disc-shaped cells without a nucleus that arise from megakaryocytes in the bone marrow.
When a vessel breaks, vascular spasm causes vasoconstriction, and the damaged endothelium exposes collagen in the extracellular matrix; von Willebrand factor binds the platelet to that surface.
The attached platelets release granules containing ADP, thromboxane A2 and serotonin, aggregate with one another and form a temporary platelet plug.
A plug built right in the hole, out of the body's own cells.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Hemostasis, StatPearlsPublished
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