T11.3 - Blood Clotting (FINISH THIS)

Question 1

what is the blood clotting cascade

Answer 1

• leads to the formation of a fibrin clot to stop bleeding
• regulated mechanism of many different factos
• extrinsic and intrinsic pathway (different card)
• each step leads to an amplification of the original signal
• very small amounts of the initial signal needed to trigger formation of the clot
• important because need to form clots quickly, at the right place and time
• thrombin is acvticated from prothrombin (sep card) that can then go on to activate other precursors
• the pathway is sustained by positive feedback

Question 2

what is the intrinsic vs extrinsic pathway

Answer 2

intrinsic pathway damaged endothelial lining of blood cells promotes binding of factor 12 (XII), which activates factor 10 (X)

extrinsic pathway trauma releases tissue factor 3 (III), which activates factor 10

→ the activation of factor 10 stimulates thrombin to be activated from prothrombin (sep card)
→ thombrin converts fibrinogen into fibrin (sep card)
→ fibrin monomers assemble by non-covalent interactions
→ this forms soft clot, which is later cross-linked by covalent bonds, catalysed by transglutaminase (factor XIII)
→ clotting process is stopped