The Structure of Resting and Activated Platelets

At first glance, the platelet is a simple cell. However, its small size hides an extremely well conserved structure that is vital for its function in both hemostasis and vascular integrity and development. A combination of electron microscopy, light microscopy, biochemical, and cell biology studies has, over the years, revealed this structure to us and allowed the important functions of the various organelles and subcellular components to be understood. This chapter reviews the structure of the resting platelet and discusses the dramatic and dynamic changes, especially in the cytoskeleton, that occur upon activation to allow platelets to carry out their primary function in hemostasis.