Concerning in-vivo regulation of the anticoagulated state by endothelium, the following is/are true:

d. Endothelial cells can secrete tissue factor

Endothelium synthesizes heparan which, like heparin, increases the affinity of ATIII for thrombin which is inactivated along with other serine proteases, including factors VII, IX and X. Thrombomodulin, in addition to binding thrombin, activates protein C which binds with protein S to inactivate factor Va. On the procoagulant side, endothelial cells produce VWF which binds platelets and are capable of secreting tissue factor.