Editing Platelet (section)

=====Morphology change=====
As shown by flow cytometry and [[electron microscopy]], the most sensitive sign of activation, when exposed to platelets using ADP, are morphological changes.<ref>{{cite journal |vauthors=Litvinov RI, Weisel JW, Andrianova IA, Peshkova AD, Minh GL |title=Differential Sensitivity of Various Markers of Platelet Activation with Adenosine Diphosphate |journal=BioNanoScience |volume=9 |issue=1 |pages=53–58 |date=2018 |doi=10.1007/s12668-018-0586-4 |pmid=31534882 |pmc=6750022}}</ref> Mitochondrial hyperpolarization is a key event in initiating morphology changes.<ref>{{cite journal |vauthors=Matarrese P, Straface E, Palumbo G, Anselmi M, Gambardella L, Ascione B, Del Principe D, Malorni W |title=Mitochondria regulate platelet metamorphosis induced by opsonized zymosan A — activation and long-term commitment to cell death |journal=The FEBS Journal |volume=276 |issue=3 |pages=845–856 |date=February 2009 |pmid=19143843 |doi=10.1111/j.1742-4658.2008.06829.x |doi-access=free}}</ref> Intraplatelet calcium concentration increases, stimulating the interplay between the microtubule/actin filament complex. The continuous changes in shape from the unactivated to the fully activated platelet are best seen via [[scanning electron microscopy]]. The three steps along this path are named ''early dendritic'', ''early spread,'' and ''spread''. The surface of the unactivated platelet looks similar to the surface of the brain–a wrinkled appearance from numerous shallow folds that increase the surface area; ''early dendritic'', an octopus with multiple arms and legs; ''early spread'', an uncooked frying egg in a pan, the "yolk" is the central body; and the ''spread'', a cooked fried egg with a denser central body.

These changes are all brought about by the interaction of the microtubule/actin complex with the platelet cell membrane and open canalicular system (OCS), which is an extension and invagination of that membrane. This complex runs just beneath these membranes and is the chemical motor that pulls the invaginated OCS out of the interior of the platelet, like turning pants pockets inside out, creating the dendrites. This process is similar to the mechanism of contraction in a [[muscle cell]].<ref>{{cite journal |vauthors=White JG |title=An overview of platelet structural physiology |journal=Scanning Microsc. |volume=1 |issue=4 |pages=1677–1700 |date=December 1987 |pmid=3324323}}</ref> The entire OCS thus becomes indistinguishable from the initial platelet membrane as it forms the "fried egg". This dramatic increase in surface area comes about with neither stretching nor adding phospholipids to the platelet membrane.<ref>{{cite journal |vauthors=Behnke O |title=The morphology of blood platelet membrane systems |journal=Series Haematologica |volume=3 |issue=4 |pages=3–16 |date=1970 |pmid=4107203}}</ref>