Flashcards
Haemostasis
Cards in this deck (12)
- 1Pathological blood clotscoronary thromboses or heart attacks, non-haemorrhagic strokes and pulmonary emboli
- 2The 2 pathwaysIntrinsic (longer) and extrinsic (shorter)
Both meet at common pathway after factor 10 is activated (FXa) - 3The blood coagulation cascade1. Proteolytic cleavage of peptide bonds activates zymogens (inactive)
2. Activated enzymes cause cascade allowing signal amplification
3. positive and negative feedback systems - 4Risks of coagulation Haemorrhage Thrombosis- Inadequate arrest of bleeding
- Inappropriate clot formation - 5The stages1. Vascular constriction - very rapid, in response to serotonin.
2. Platelet activation and plug formation - temporary platelet plug made in seconds.
3. . Coagulation Cascade and Fibrin Clot Formation – minutes.
4. . Clot dissolution - takes days. - 6The common pathwayFactor X activated to FXa
This activates prothrombin to thrombin
This activates fibrinogen to fibrin
This activates Factor XIII to FXIIIa which causes hard clot - 7Control of coagulation The glutamic acid domaincontains 10 -carboxyglutamate (Gla) residues (produced by Vit. K-dependent carboxylation) which serve as Ca2+-binding sites to attach the polypeptide to phospholipid (PL) micelles.
- 8What is Vit K?a cofactor
- 9Examples of clotting inhibitorsDicumarol (coumadin) and Warfarin.
- 10ProthrombinProthrombin contains 10-12 glutamic acid (Glu) residues
- This is required for phospholipid binding via Calcium. - 11Haemophilia A- Sex-linked recessive
- FVIII (cofactor) gene, Xq28, is mapped and mutated
- The severity of haemophilia emphasises the importance of the intrinsic pathway. - 12Factor V Leiden - Risk factor for Thrombosis- Factor V gene mutated so cannot be degraded
- Maybe a cause of venous thrombosis
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- BIOL 135: Diagnosis in Biomedical science Flashcards on Haemostasis, created by Jumael Zafar on 11/05/2019.
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- Jumael Zafar
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