Clotting Vocab

Hemostasis

Process that stops bleeding at the site of an injury

Fibrin

An insoluble protein that forms a fibrous mesh to impede blood flow

Hageman Factor (XII)

Initiates the intrinsic pathway when activated by contact with negatively charged molecules

Tissue factor (III)

A protein present in tissue cells that initiates the extrinsic pathway of blood coagulation

Factor X

Clotting factor that activates the common pathway and is part of both the intrinsic and extrinsic pathways

Prothrombin

A plasma protein that is converted into active thrombin during coagulation

Fibrinogen

A soluble plasma protein that is converted to insoluble fibrin during clotting

Plasmin

An enzyme that dissolves the fibrin of blood clots

Intrinsic pathway

The clotting pathway that begins with trauma inside the vascular system, and is activated by platelets, with no external trauma

Extrinsic pathway

The clotting pathway that begins with trauma to the blood vessel or surrounding tissues, initiating the release of tissue factor (Factor III)

Prothrombinase complex/prothrombin activator

Factor X combines with Factor V and calcium to form the enzyme that converts prothombin to thrombin

Thrombin

An enzyme that converts fibrinogen to fibrin during blood clotting

Platelet derived growth factor (PDGF)

Stimulates proliferation of smooth muscle cells and fibroblasts to rebuild blood vessel wall

Heparin

Short-acting anticoagulant that opposes prothrombin

Tissue factor pathway inhibitor (TFPI)

Inhibits activation of Factor VII in extrinsic pathway

Bradykinin

Vasodilator released to relax and restore blood flow in the circulation

Antithrombin

Inactivates Factor X

Plasminogen activator (tPA)

Converts plasminogen to plasmin

Protein C system

Inactivates clotting factors involved in the intrinsic pathway

Vascular endothelial growth factor (VEGF)

Stimulates proliferation of endothelial cells for regeneration of endothelial lining

Von Willebrand factor

Plasma protein that helps platelets bind to exposed collagen and endothelial lining

ADP

Helps additional platelets adhere to the injury site, reinforcing and expanding the platelet plug

Serotonin

Maintains vasoconstriction and enhances platelet aggregation