How do platelets divide and multiply without having a nucleus?

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Moreover, how do they know they are needed, without the guidance of a nucleus?

In: Biology

Platlettes are fragments of a progenitor cell called a megakaryocyte usually found in the bone marrow.

https://en.m.wikipedia.org/wiki/Megakaryocyte

They are always present in your bloodstream. Once the clotting Cascade is activated by any of several mechanisms, they are activated which causes them to clump together and are then trapped by fibrin strands to form the solid part of the clot.

I am a NYS liscensed medical technologist working in a large teaching hospital in the hematology / coagulation lab

Edit: typo

Platelets don’t reproduce. The average lifespan of a platelet is 8-9 days. All of our blood cells are made in our bone marrow from stem cells that differentiate into all of the different types of blood cells we have. Your marrow is constantly making new platelets (and other blood cells) to replace ones that have worn out. Platelets, like all blood cells, circulate freely in your blood. When a blood vessel is damaged and blood leaks out, there will be platelets already there. They stick to the edges of the wound and release chemicals that attract more platelets to plug the wound. Other chemicals in your blood called clotting factors cause strands of a protein called fibrin to stick together and seal the inside of the wound

>Moreover, how do they know they are needed, without the guidance of a nucleus?

They don’t. They stick wherever they can, which happens to be wherever a blood vessel is disrupted.