Platelets are cell parts, not cells

There's not too much to say about platelets... but they are still quite different from RBCs and WBCs, so they deserve their own page.

Hemocytoblasts give rise to megakaryocytes, which make platelets. The megakaryocytes simply break off pieces of themselves, and then regrow so they can break off more and more pieces. These pieces enter the blood and become platelets. So they have a membrane around them, but no nucleus.

Platelets don't have it as lucky as RBCs... they only live around 10 days.

Platelets are involved in repairing the blood system. You will see in the Damage Control page that they are the things that form clots. They do even more than that toward repairing damaged blood vessels, but that will have to wait for the Damage Control page. They can also crawl around a bit by amoeboid locomotion, until they get stuck in a place of damage.

That's not so hard, huh?