4D 1.1 Biochem i.6 Flashcards
Q19 drugs that work as a platelet ADP receptor antagonist are referred to as what.
AP drugs
Q41what does anti-thrombin III do
A plasma protein that forms an irreversible complex with thrombin
Q44 what are the 4 functions of thrombin
Converts Fibrinogen to Fibrin
Activates Factor XIII to stabilise Fibrin mesh by crosslinking
Enhances its own activation by positive feedback
Enhances platelet aggregation
Q26 what does A clot on top of platelet plug do
strengthens the plug and reinforces the seal
Q11 Platelets can be ACTIVATED by several factors: what are they
- ADP (adenosine diphosphate) - released by platelets, erythrocytes & endothelial cells
- COLLAGEN – in the connective tissue, exposed by vessel damage
- THROMBIN – made by enzymatic cleavage of prothrombin
- PAF – platelet activating factor (phospholipid) from the vessel wall & other cells
Q50 wound healing Occurs by 4 continuous, overlapping and precisely programmed phases
Rapid Haemostasis
Appropriate Inflammation
Proliferation
Tissue Remodelling
Q30 which factor converts prothrombin to thrombin
Factor X (10), Factor V (5), Ca2+, PF3
Q21 excessive bleeding can occur through acquired disorders such as
Vitamin C deficiency
Excessive exogenous (gym)
Endogenous glucocorticoids (drugs)
Q47 warfarin and dicoumarol are examples of
Vitamin k antagonists
Q2 Haemostasis is a complex system involving 3 major steps, what are they?
1 vascular spasm.
2 formation of a platelet plug.
3 blood coagulation (clotting)
Q32 which factor from the intrinsic pathway converts factor x (10)
Factor IX (9), Factor VIII (8), ca2+, PF3
Q4 Muscle cells contract
Constriction reduces blood flow
limits blood loss
occur during?
Vasoconstriction
Q48 anti-thrombin (synthesised in the liver), Heparin (synthesised in mast cells), protein c and s (synthesised in liver) and tissue factor pathway inhibitor, are all responsible for what
Preventing inappropriate clotting
Q36 what causes the fibrin to cross link
Activated factor XIII (XIIIa)
Q12 What are the Effects of ACTIVATION on Platelets:
- Change shape from disc to sphere with extended pseudopodia
- Granules release in aid of haemostasis e.g ADP, serotonin, fibronectin and vWF
- Aggregate
- Adhere to vessel wall
- Synthesis thromboxane
Q8 where are platelets derived from
small fragments derived from bone marrow cells called megakaryocytes
Q27 what is fibrin
insoluble, threadlike molecule, which forms a loose, mesh that traps blood cells
Q10 under what conditions, allow platelets to not stick to the endothelium
Normal
Q13 Outline the stages of formation for a platelet plug
Platelet adhesion to vessel wall -> Platelet activation -> Platelet aggregate (build Platelet mass) -> mass forms primary haemostatic plug -> plug is stabilised by fibrin.
Q38 protein c is activated by what
Thrombin