Ultra structurally , endothelial cells contain
ref Robbins 9/e p76 Weibel-Palade bodies (WPBs) are the storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and hea. They store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in hemostasis and inflammation.
Weibel palade bodies
Langerhan's granules
Abundant glycogen
Kallikrein
General anatomy