Blood Clotting Summary

[justadream]

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Is it worth memorizing the pathway and factors?

This is what I have in my notes (am I missing any critical factor/molecule)?


Intrinsic: clotting factors from blood
Extrinsic: clotting factors from damaged tissues and blood vessels

The two pathways unite to create thrombin.

1) Factor Xactiveconverts Prothrombin (Vitamin K needed to make this) to Thrombin
2) Thrombin converts Fibronigen to Fibrin
3) Fibrin fibers are crosslinked by an enzyme (transglutaminase) to form a clot

Ca2+is needed in both mechanisms.
Fibronigen and Prothrombin are both made in the liver.

 

[tdod]

i think it's overkill to memorize clotting factors. In my opinion, just knowing that thrombin and fibrin are involved in clotting.

 

[sillyjoe]

Totally overkill. Familiarity with the process can help, but memorization certainly isn't necessary.

 

[The Brown Knight]

Yup too much detail.
Though you should be familiar that the liver manufactures fibrinogen and platelets come from bone marrow. Passage should provide you with specific pathways.

 

[Czarcasm]

The main takeaways from blood clotting, aside from what you mentioned, is that anticoagulants such as citrate chelate calcium and prevent clotting from occuring. The pathways themselves aren't important, but I think knowing calcium is involved with each step is. Also, positive feedback is significant here. You have thrombin activating additional clotting factors. Also worth noting, the final step of the whole cascade: thrombin converts fibronogen to fibrin. Fibrin forms a thread-like mesh with platlets to form the thrombus (clot). Anything beyond that I think is out of scope, but I think this information is sufficient for what's mentioned on AAMC outline.

 

[Dhooy7]

I've been looking all over but am very confused why vasoconstriction results from a blood clot. How does vasoconstriction decrease blood flow. The way I'm thinking about it is that with the same flow of blood the radius is smaller so there would be an increased flow of blood. Or does the body have a way to slow down blood flow when it vasoconstricts?

 

[Cytarabine]

I've been looking all over but am very confused why vasoconstriction results from a blood clot. How does vasoconstriction decrease blood flow. The way I'm thinking about it is that with the same flow of blood the radius is smaller so there would be an increased flow of blood. Or does the body have a way to slow down blood flow when it vasoconstricts?

Vasoconstriction occurs both reflexively if there's endothelial damage and through local release of vasoconstrictive substances. There is not the same flow of blood. Your small blood vessels are in parallel with one another