Platelets in normal homeostatic mechanisms

Description:

• minute round or oval discs
• 2 microns in diameter
• fragments of megakaryocytes
• [which disintegrate into platelets while still in bone marrow]
• 150,000 — 400,000 / ml

Homeostasis

participate in 2 ways:

1) in normal tissues: platelets clump together to plug small defects which appear continuously in the walls of small blood vessels.

2) when blood vessels are injured: platelets contribute to the process of clot formation and retraction as well as releasing serotonin which reduces blood flow by vasoconstriction of the damaged blood vessel.

K. C. Potger
Copyright © 2001