blood_and_immune_upper_slim has characteristic develops from megakaryocyte progenitor cell megakaryocyte https://cellxgene.cziscience.com/cellguide/CL_0000556 megalocaryocyte FMA:83555 Megakaryocytes are reportedly CD181-positive and CD182-positive. CALOHA:TS-0611 A large hematopoietic cell (50 to 100 micron) with a lobated nucleus. Once mature, this cell undergoes multiple rounds of endomitosis and cytoplasmic restructuring to allow platelet formation and release. A megakaryocyte is a large, unique, and complex cell type found primarily in the bone marrow, the spongy, semi-solid tissue located in the medullary cavities of certain bones. The term ‘megakaryocyte’ is derived from the Greek 'mega', meaning great, and 'karyon', referring to the nucleus. Megakaryocytes are characterized by their large size, typically with a diameter of 50-100 µm in humans, and the presence of a multilobulated nucleus; they are the largest hematopoietic cells in the bone marrow but also the rarest cells. The primary function of a megakaryocyte is the production of platelets, also known as thrombocytes. Platelets are small, anucleate cell fragments that play a crucial role in the process of hemostasis, the arrest of blood loss from a damaged blood vessel. The process begins when the megakaryocyte extends long, branching processes called proplatelets, into the sinusoidal blood vessels present in the bone marrow. These proplatelets then fragment into the discoid structures recognized as platelets. Each megakaryocyte can produce thousands of platelets during its lifespan. Apart from platelet production, megakaryocytes are involved in several other functions. They express immune-sensing receptors such as Fc-γ receptor and Toll-like receptors and produce factors such as platelet factor 4 and platelet-derived growth factor that can stimulate the immune system. Also, in certain pathological conditions, megakaryocytes release TGF-β and PDGF and contribute to bone marrow fibrosis, a condition characterized by excessive accumulation of fibrous tissue in the bone marrow leading to anemia. Recent studies have also highlighted the role of megakaryocytes in regulating hematopoiesis, the process of blood cell production. They can influence the bone marrow microenvironment and control the behavior of hematopoietic stem cells, the progenitors of all types of blood cells. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) BTO:0000843 megacaryocyte megalokaryocyte myeloid cell erythroid lineage cell Homo sapiens euploid