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Flashcards in Physiopathology Final Deck (184)
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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)

1

When does blood allow for plug to occur

when healing needs to happen

2

What is hemostasis a property of

BV and blood

3

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

4

Anti-platelet effects of intact endothelium (4)

1. insulates platelets from subendothelial collagen
(physical barrier between collagen and platelets)
2. Prostacylcin (PGI2) synthesis- inhibits platelet agg
3. ADPase synthesis- inhibits platelet agg
4. Nitric oxide synthesis- vasodilation & inhibit platelet agg

5

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

6

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

7

Anti-coagulant effects of intact endothelium

Heparin like molecule synthesis--> activates anti-thrombin III (degrades thrombin)

8

Effect of no thrombin on the coag system

Shuts off coag

9

What is the coag system

Release of fibrin to form lattice like system to plug up certain things
no coag system? No platelet agg

10

What turns on synthesis of antithrombin III

Herparin like factor

11

Fibrinolytic property of intact endothelium

tPA synthesis --> converts plasminogen to plasmin

12

What does plasmin do

Degrades fibrin (chews up clot)

13

Ischemic stroke

Patient produces fibrin clot in artery somewhere--> inject with tPA to clear clot

14

Hemorrhagic stroke?

Give tPA and you will kill them--> they can't clot

15

Pro-thrombotic properties of damaged endothelium (4)

1. Von Willebrand's factor
2. Tissue factor synthesis
3. Platelet activating factor (PAF)
4. t-PA inhibitor synthesis

16

von-Willebrand Factor

- Pro-thrombotic property of damaged endo
- Essential for platelet adhesion
- Expressed on surface and give platelets region to bind to

17

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

18

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

19

Platelet activating factor as protrombotic property of damaged endo

damaged endo + PAF + platelets

20

t-PRA inhibitor ensures what

Clot will remain
*Plays important role in prothrombotic property of damaged endo

21

What are the "bricks" of a thrombus? Cement?

Bricks: platelets
Cement: fibrin

22

Platelet actions oppose the action of what

endothelium

23

Platelets secrete what (5)

Thromboxane (TXA2), ADP, Factors V and VIII, calcium

24

What do activated platelets bind to

Exposed collagen--> vWF

25

Activated platelet role in coagulation cascade

Initiates cascade (role of calcium and phospholipid complex)

26

"Temporary plug"

becomes definitive with formation of fibrin from thrombin = fused mass of platelets

27

Young clot appearance vs old clot appearance

Young: red, currant jelly
Old: can become permanent structures within BV

28

Coagulation System activated by who

- Activated by factor XII (hageman) or tissue factor
- End product is formation of fibrin monomers
- Fibrin is "cement" of thrombus

29

Thrombus

- An aggregate of platelets, fibrin and blood cells within the non-interrupted vascular system
- Adherent to vascular endothelium (vs a post-mortem blood clot) *Must be attached to BV wall!
- May arise in arterial or venous circulation