in the vascular bed , endothelial cells provide a nonthrombogenic lining layer and release small amounts of tissue plasminogen activator into the circulation , maintaining patency of the vascular bed , whereas the alveolar epithelial surface is replete with active enzymes of the extrinsic pathway of coagulation as well as urokinase .
C0225336
endothelial cells
C0042071
urokinase