Editing Platelet (section)

===Development===
[[File:Blood cells differentiation chart.jpg|thumb|Platelets derive from multipotent marrow stem cells.]]
* Megakaryocyte and platelet production is regulated by [[thrombopoietin]], a hormone produced in the kidneys and liver.
* Each megakaryocyte produces between 1,000 and 3,000 platelets during its lifetime.
* An average of 10<sup>11</sup> platelets are produced daily in a healthy adult.
* Reserve platelets are stored in the spleen and are released when needed by splenic contraction induced by the sympathetic nervous system.
[[File:1908 Platelet Development.jpg|thumb|Platelets extruded from megakaryocytes]]
* The average life span of circulating platelets is 8 to 9 days.<ref>{{cite journal |vauthors=Harker LA, Roskos LK, Marzec UM, Carter RA, Cherry JK, Sundell B, Cheung EN, Terry D, Sheridan W |title=Effects of megakaryocyte growth and development factor on platelet production, platelet life span, and platelet function in healthy human volunteers |journal=Blood |volume=95 |issue=8 |pages=2514–22 |date=April 2000 |pmid=10753829 |doi=10.1182/blood.V95.8.2514}}</ref> Life span of individual platelets is controlled by the internal apoptotic regulating pathway, which has a Bcl-x<sub>L</sub> timer.<ref>{{cite journal |vauthors=Mason KD, Carpinelli MR, Fletcher JI, Collinge JE, Hilton AA, Ellis S, Kelly PN, Ekert PG, Metcalf D, Roberts AW, Huang DC, Kile BT |title=Programmed anuclear cell death delimits platelet life span |journal=Cell |volume=128 |issue=6 |pages=1173–86 |date=March 2007 |pmid=17382885 |doi=10.1016/j.cell.2007.01.037 |s2cid=7492885 |doi-access=free}}</ref>
* Old platelets are destroyed by [[phagocytosis]] in the spleen and liver.