Which cell type in the bone marrow is the direct precursor to platelets?

Which cell type in the bone marrow is the direct precursor to platelets?

• A. Megakaryocyte
• B. Monocyte
• C. Lymphocyte
• D. Eosinophil

Answer: (A)

Platelet production in the bone marrow happens through thrombopoiesis, starting with the megakaryocyte. Megakaryocytes are large, polyploid cells that extend cytoplasmic processes into nearby blood vessels; their cytoplasm fragments into small, anucleate platelets that enter the circulation. This direct link means the megakaryocyte is the cell type that gives rise to platelets. Other listed cells belong to different blood lineages and do not produce platelets: monocytes mature into macrophages, lymphocytes are immune cells, and eosinophils are granulocytes involved in allergic responses and parasitic infections.

Platelet production in the bone marrow happens through thrombopoiesis, starting with the megakaryocyte. Megakaryocytes are large, polyploid cells that extend cytoplasmic processes into nearby blood vessels; their cytoplasm fragments into small, anucleate platelets that enter the circulation. This direct link means the megakaryocyte is the cell type that gives rise to platelets.

Other listed cells belong to different blood lineages and do not produce platelets: monocytes mature into macrophages, lymphocytes are immune cells, and eosinophils are granulocytes involved in allergic responses and parasitic infections.