FACTORS WHICH PROMOTE BLOOD FLUIDITY Normal Hemostasis Natural Anticoagulants Protein C ●Protein S ◆Antithrombin Ill Endothelial-Derived Anti-Platelet Substances ◆Nitric Oxide ·Prostacyclin(PGl2) Fibrinolytic System "clot busters" ·Plasmin 。Plasminogen Tissue Plasminogen Activator(tPA) Department of Pharmacology Howard University College of Medicine