Platelets are made primarily in the bone marrow. They are produced from large bone marrow cells called megakaryocytes, which fragment to release platelets into the bloodstream
. Megakaryocytes develop in the bone marrow and extend cytoplasmic projections called proplatelets, from which platelets are formed and released
. In addition to the bone marrow, some megakaryocytes and platelet production can also occur in lung tissue, but the bone marrow is the main site
. Thus, the bone marrow is the central location where platelets are generated from megakaryocytes before entering circulation.
