Lecture 8 - Coagulation (Classic) Flashcards
most coagulation factors are synthesized in the
liver
factors circulate in __ form
inactive
factor 4
calcium
factor 2a
thrombin
factor 1
fibrinogin
the classic cascade model for coagulation includes
extrinsic, intrinsic and common pathways
vitamin K dependent coagulation factors (essential!!!)
2 (thrombin), 7, 9, 10
__ states can cause body to not process fat and end up with vitamin K deficiency = not able to clot well due to factors 2, 7, 9, 10 compromised
maldigestion dz (vitamin K is fat soluble)
vitamin K dependent enzyme in the __ is essential for the sythesis of vitamin K-dependent factors
liver
__ intoxication targets vitamin K dependent factors = can’t clot!
anticoagulatant rodenticides (factor 7)
factor __ has the shortest half life
7
what pathway occurs when negatively charged endothelium tissue is damaged
extrinsic/tissue factor pathway (factor 7/Ca/Tissue Factor)
How is extrinsic pathway initiated
exposed subendothelial cells and tissue factor
factor 7 binds and is activated by Ca
7a/Ca/Tissue factor activates
factor 10 (and factor 9)
Factor 10a binds to
5a on the platelet, Ca++ brings negative charged complex to the negative surface bc it is +
Factor 10a/5a/Platelet complex activates
small amounts of prothrombin (factor 2) to thrombin (2a)
Thrombin (2a) converts __ and __
- fibrinogen (factor 1) into fibrin monomers AND
2. factor 13 into 13a to cross link the fibrin monomers to form stable cross linked fibrin/secondary hemostatic plug
What does factor 13a do?
cross link the fibrin monomers to form stable cross linked fibrin/secondary hemostatic plug
what are 2 main feedback loops to amplify the extrinsic pathway
- 10a activates 7 to 7a (starts whole cascade over)
2. 7a activates factor 9 to 9a which activates common pathway
propagation is initiated by thrombin (factor 2) which activates everything and is called the __
thrombin burst = majority of fibrin forms from this!
__ converts fibrin monomers into cross linked fibrin
thrombin (2a) (via 13a)
__ initiates the thrombin burst
thrombin (2a)
Factor 12 (hageman), HMWK, and prekallikrein are part of factors used __ (outside body) to activate coagulation system by physical contact. in the actual body they are not required to start the coagulation process. They have more involvement in __ pathways and __ and __ activation.
in vitro
inflammatory and complement, fibrolysis
Factor 12, HMWK, prekallikrein are __ acivated by physical contact and __ are not important to hemostasis, but it’s function in hemostasis is useful in lab tests)
in vitro (outside body), in vivo (inside body)
is the coagulation cascade the main function of factor 12 (hageman factor)
no, it is a minor function (it also involved in inflammation, complement and fibrolysis activation)
hemostasis is the interaction of BV, platelets, and coagulation factors to stop hemorrhage without
obstructing blood flow (balance between fibrin clot formation and degradation)
__ is initiated at the same time as coagulation
fibrinolysis (clot degradation)
important fibrinolysis/coagulation inhibitor factors
- plasmin
- antithrombin 3
- protein C with protein S
- Tissue Factor Pathway Inhibitor (TFPI)
Tissue factor activates tissue plasminogen activator which converts
plasminogen to plasmin (fibrionlysis)
plasmin breaks down what 3 things
fibrinogen, fibrin monomers and cross linked fibrin
