Expert: Joy Ramos - 5/4/2006

Question
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Followup To
Question -
Where in the mechanism of blood coagulation does Factor VIII play a role?....
Answer -
Hi, Jay! I did a little research on the net and this is what I came up with.  When a blood vessel is damaged, the hole is plugged up by a blood clot so that repair can continue. Clotting is initiated by the contact of platelets with collagen fibers in the blood vessel lining. This adhesion is mediated by von Willebrand factor, which is ordinarily bound to Factor VIII to keep it stable.  Factor VIII also plays a role when it is activated by thrombin (activated form of prothrombin by previous steps in the cycle) and releases it from being bound to vWF. Once active, it's denoted as VIIIa.
FVIIIa is the co-factor of FIXa and together they form the "tenase" complex which activates FX and so the cycle continues.
Blood coagulation is a complex series of cascades and many proteins are involved in the process. I assumed you already have background knowledge on this topic and just want to clarify Factor VIII's role so that's what I highlighted here. Hope this helps!

IN WHICH CASE CAN U EXPLAIN THE NORMAL MECHANISM BY WHICH BLOOD COAGULATES FOLLOWING DAMAGE TO A BLOOD VESSEL?


Answer
Hi, Jay. It's really not a topic I'm very familiar with so I'll direct you to public websites that are very comprehensive and will do a much better job explaining it than me.

a. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Clotting.html

b. http://www.answers.com/topic/coagulation.

Good luck!