Review Article
Overview of Platelet Physiology: Its Hemostatic and Nonhemostatic Role in Disease Pathogenesis
Table 2
A comparison of endothelial and platelet properties (adapted from Warkentin et al., 2003 [
21]).
| | Endothelium | Platelets |
| Nucleus | Yes | No | mRNA | Lots | Little but active | Cell dimensions | Highly variable: up to 100 M length in large vessels | Diameter ~4 M, volume 7–12 fL (inversely proportional to platelet count) | Life span | Long (months to years) | Short (7–9 days) | Daily production | Not known | 2.5 × 1011 | Circulating | Few | Most (normally 1/3 sequestered in spleen; may become sequestered on activated endothelium) | Diagnostic markers | Indirect and not clinically useful | CBC, peripheral smear, platelet function studies | Origin | Bone marrow | Bone marrow | Storage granules | Weibel-Palade bodies | α granules, dense granules, lysosomes | Partial list of storage components | vWf, P-selectin, multimerin | vWf, P-selectin, multimerin, fibrinogen, PDGF, TGF-β, IL-1, VEGF, angiopoietin, RANTES, PF4, ADP, ATP, serotonin |
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