Physiopathology Final Flashcards
When does blood allow for plug to occur
when healing needs to happen
Define hemostasis
- Blood vessels maintain fluid consistency of blood
- Maintenance of clot-free blood within the vascular system while allowing for the formation of a solid plug of blood under conditions of vessel wall injury (ex: thrombosis)
What is hemostasis a property of
BV and blood
Tunica intima is lined with what
Single layer of vascular endothelium that has to maintain its integrity–> non-damaged, non-inflammatory possess anti-platelet effects
Anti-platelet effects of intact endothelium (4)
- insulates platelets from subendothelial collagen
(physical barrier between collagen and platelets) - Prostacylcin (PGI2) synthesis- inhibits platelet agg
- ADPase synthesis- inhibits platelet agg
- Nitric oxide synthesis- vasodilation & inhibit platelet agg
ADPase synthesis in anti-platelet effects
Inhibits platelet agg; a lot of ADP? we are low energy situation–> can’t feed biological system. high ADP? high agg so produce ADPase to remove ADP–> inhibit agg
Nitric oxide synthesis in anti-platelet effects
Constitutively produced, sets normal vascular tone in body–> we always have some form of vasodil.
- Dilated so platelets go further away from eachother–> decreases agg
Anti-coagulant effects of intact endothelium
Heparin like molecule synthesis–> activates anti-thrombin III (degrades thrombin)
Effect of no thrombin on the coag system
Shuts off coag
What is the coag system
Release of fibrin to form lattice like system to plug up certain things
no coag system? No platelet agg
What turns on synthesis of antithrombin III
Herparin like factor
Fibrinolytic property of intact endothelium
tPA synthesis –> converts plasminogen to plasmin
What does plasmin do
Degrades fibrin (chews up clot)
Ischemic stroke
Patient produces fibrin clot in artery somewhere–> inject with tPA to clear clot
Hemorrhagic stroke?
Give tPA and you will kill them–> they can’t clot
Pro-thrombotic properties of damaged endothelium (4)
- Von Willebrand’s factor
- Tissue factor synthesis
- Platelet activating factor (PAF)
- t-PA inhibitor synthesis
von-Willebrand Factor
- Pro-thrombotic property of damaged endo
- Essential for platelet adhesion
- Expressed on surface and give platelets region to bind to
Von-Willebrand disease
-Mild, moderate or severe
-Severity determined by degree of loss of expression of VW factor
- Usually females of repro age
Sx: heavy menstrual flow
Mod/Severe? unable to maintain preg; hemorrhaging won’t occur of baby into wall–> spontaneous abortion
Tissue factor synthesis as a pro-thrombotic property of damaged endo
- Glycoprotein which activates coag system
- One of triggers for coag system
- Damage endo turns on tissue factor–> turns on coag system
Platelet activating factor as protrombotic property of damaged endo
damaged endo + PAF + platelets
t-PRA inhibitor ensures what
Clot will remain
*Plays important role in prothrombotic property of damaged endo
What are the “bricks” of a thrombus? Cement?
Bricks: platelets
Cement: fibrin
Platelet actions oppose the action of what
endothelium
Platelets secrete what (5)
Thromboxane (TXA2), ADP, Factors V and VIII, calcium