Chapter 17.4 - clot breaking down Flashcards
What is serum?
Plasma minus the clotting proteins
What are the steps of clot retraction?
Actin and myosin contracts, this pulls on fibrin strands which causes squeezing serum from clot and draws ruptured blood vessel edges together
Which growth factors are present with the healing process
Platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF)
What does PDGF do?
Stimulates division of smooth muscle cells and fibroblasts to rebuild blood vessel wall
What does VEGF do?
Stimulates enothelial cells to multiply and restore endothelial lining
What is fibrinolysis?
Breaking down the clot (so the vessel won’t be blocked)
Which activator, protein and factor play a role in the conversion process?
Tissue plasminogen activator (tPA), factor XIIa and thrombin
What does plasminogen do?
It is a plasma protein that is trapped in the clot, which will be converted to plasmin; a fibrin digesting enzyme
Which two mechanisms limit clot growth?
Swift removal and dilution of clotting factors and inhibition of activated clotting factors
What are examples of the inhibition?
Antithrombin III, Heparin in basophil and mast cells and Protein C in the liver
What does antithrombin III do?
Inactivates any unbound thrombin
What does Protein C do?
Inhibits activity of intrinsic pathway clotting factors
Which factors prevent platelet adhesion
?
Smooth endothelium prevents platelets from clinging and endothelial cells secrete antithrombic substances
What is thromboembolic?
A major type of disorder in hemostasis which result in undesirable clot formation
What are bleeding disorders?
Abnormalities that prevent normal clot formation
