Platelets

Definition

Platelets are small, disc-shaped cell fragments in the blood that are essential for clotting. They prevent excessive bleeding by clumping and forming plugs in blood vessel injuries.

5 Must Know Facts For Your Next Test

1. Platelets are produced in the bone marrow from large cells called megakaryocytes.
2. The average lifespan of a platelet is about 7-10 days.
3. Platelet count in healthy individuals ranges from 150,000 to 450,000 per microliter of blood.
4. They release chemicals that help initiate and control the clotting process.
5. Thrombocytopenia is a condition characterized by abnormally low levels of platelets.

Review Questions

• What role do platelets play in the circulatory system?
• Where are platelets produced?
• What is thrombocytopenia?

Related terms

Hemostasis:

The process by which the body stops bleeding and maintains blood in a fluid state within the vascular system.

Megakaryocytes: Large bone marrow cells responsible for the production of platelets.

Thrombin: An enzyme that converts fibrinogen to fibrin during blood clot formation.