Endothelial cell
Endothelial cells make up the endothelium which lines the inner surface of the lymphatic system, blood vessels and also the heart. Among their functions are coagulation, blood vessel formation, inflammation, relaxation of arterial smooth muscle and fibrinolysis.
References:
Michiels, C. (2003) Endothelial Cell Functions.Journal of Cellular Physiology. 196(3). pp. 430-432