Thrombopoiesis refers to the process of thrombocyte generation. Thromobocytes are ligations of the cytoplasm from megakaryocytes. A single megakaryocyte can give rise to thousands of thrombocytes.
The term "thrombocytopoiesis" is sometimes used to emphasize the cellular nature.
Thrombopoietin stimulates megakaryopoiesis, the process of megakaryocyte maturation and differentiation. Thrombopoietin, upon release, binds to its receptor, c-mpl, found on megakaryocyte progenitor cells. Following binding, intracellular signalling leads to megakaryocyte growth, maturation, membrane stability, platelet granule formation and the demarcation of the cytoplasm into regions destined to fragment into mature platelets. These "proplatelet processes" further fragment into platelets. This last step of proplatelet process and platelet formation, in vitro, has been shown to be independent of thrombopoietin.