Abstract
Megakaryocytes are large polyploid cells present of the bone marrow, which produce the blood platelets or thrombocytes, small disk-shaped cytoplasmic fragments that circulate in the blood and are essential components of the haemostasis system. Formation and release into the blood is under the primary regulation of thrombopoietin, a glycoprotein produced in the kidney and liver. During differentiation of megakaryocytes, continued DNA replication in the presence of abortive mitosis leads to the formation of polyploid nuclei, a process called endomitosis. It has been shown that polyploidisation is connected with the suppression of stathmin, a microtubule-regulatory protein that has a major role in the formation of the mitotic spindle. Platelets are pre-formed in the cytoplasm of megakaryocytes at sites of protrusions, called proplatelets. A megakaryocyte may form 10–20 proplatelets from the tips of which the platelets are released. Maturing platelets become filled with organelles and granules, which move from the megakaryocyte cell body to the tips of the proplatelets.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Ebbeling L, Robertson C, McNicol A, Gerrard JM (1992) Rapid ultrastructural changes in the dense tubular system following platelet activation. Blood 80: 718
Fuhrman B, Brook GI, and Aviram M (1992) Proteins derived from platelet alpha granules modulate the uptake of oxidized low density lipoprotein by macrophages. Biochim Biophys Acta 1127: 15
Hartwig J and Italiano J (2003) The birth of the platelet. J Thromb Haemost 1: 1580
Italiano IE and Shivdasani RA (2003) Megakaryocytes and byond: the birth of platelets. J Thromb Haemost 1: 1174
Kaushansky K (2003) Thrombopoietin: a tool for understanding thrombopoiesis. J Thromb Haemost 1: 1587
Mahaut-Smith MP, Thomas D, Higham AB, Usher-Smith JA, Hussain IF, Martinez-Pinna J, Skepper IN, and Mason MI (2003) Properties of the demarcation membrane system in living rat megakaryocytes. Biophys J 84: 2646
Rubin CI, French DL, and Atweh GF (2003) Stathmin expression and megakaryocyte differentiation: A potential role in polyploidy. Exp Hematol 31: 389
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2010 Springer-Verlag/Wien
About this chapter
Cite this chapter
Pavelka, M., Roth, J. (2010). Megakaryocyte and Thrombocyte. In: Functional Ultrastructure. Springer, Vienna. https://doi.org/10.1007/978-3-211-99390-3_180
Download citation
DOI: https://doi.org/10.1007/978-3-211-99390-3_180
Publisher Name: Springer, Vienna
Print ISBN: 978-3-211-99389-7
Online ISBN: 978-3-211-99390-3
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)