Coagulation Flashcards
Hemostasis
Cessation of Bleeding
What are the three separate but overlapping hemostatic mechanisms that occur when the endothelial lining of a blood vessel is exposed to collagen proteins?
1) Vasoconstriction
2) The formation of a platelet plug
3) The production of a web of fibrin proteins that penetrates and surrounds the platelet plug.
Platelets that have attached together release what chemical that causes vasoconstriction?
Seratonin
What is a hematoma?
The accumulation of blood in the tissues
Why don’t capillaries constrict?
They are a single layer, they don’t have a muscular component.
Another name for Platelets
Thrombocytes
What cells maintain the health and integrity of the endothelium?
Platelets
What is the term for an insufficient number of platelets in the blood?
Thrombocytopenia
Bruising caused from petechiae
Purpura
Epistaxis
Nose bleed
What causes compression and strengthening of the platelet plug?
The filaments found in platelets. They are similar to actin and myosin found in muscle cells.
What is the primary sealer of breaks in the vessel wall?
Platelet Plug
What chemicals do endothelial cells of blood vessels secrete to inhibit platelet aggregation in the absence of blood vessel damage, and also act as vasodilators?
Prostacyclin (PGI2- a type of prostaglandin) Nitric Oxide (NO)
What is CD39? Where is it located?
CD39 is an enzyme that breaks down ADP int he blood to AMP and Pi. CD39 inhibits platelet aggregation so that when activated platelets release ADP they don’t stick to the vessel wall and to each other. This is to help insure blood flow around the forming clot.
CD39 is found in the plasma membrane of endothelial cells.
What protein produced by endothelial cells binds to both collagen and platelets? What is its role?
von Willebrand’s factor. It helps prevent the force of passing blood from pulling platelets off the collagen.
Binding of glycoprotein receptors on the platelet’s membrane to VWF helps to anchor the platelets to the site of injury.
