Platelets or thrombocytes (PLT) are cell fragments derived from megakaryocytes with hemostatic function in the blood stream. PLT are anucleated but contain functioning mitochondria that play a critical role in PLT activation.
Reference: Garcia-Souza 2014 Int J Biochem Cell Biol
- In the quiescent state, PLT have a discoid shape, measuring 2.0 to 5.0 µm in diameter, 0.5 µm in thickness and having a cell volume of 6 to 10 femtoliters. 
- White JG (2007) Platelets 2nd Edition, Academic Press, Burlington. White 2007 Platelets