Primary function

For sealing, hemostasis  They form the 2nd major component of the hemostatic system Note: The 1st major component for the maintenance of Hemostatic system are the Blood vessels. (Contains the cell if there is wound, and the platelets will seal the site of injury or wound)  They have sealing function – they aid in the formation of thrombus, or plug (Platelet Plug Formation to stop the breakage in the endothelial system) when there is a break in the circulatory system.