Understanding Hemophilia The Way Blood Clots
How Blood Clots:
Blood clotting, or coagulation, is the process that controls bleeding. This process involves as many as 20 different plasma proteins, or blood clotting factors. Normally, a complex chemical process occurs using these clotting factors to form a substance called fibrin that stops bleeding.1
When a person whose blood factor levels are normal experiences bleeding, the following series of events are set in motion:2
Normal clotting sequence.
Interrupted clotting sequence.
Blood vessels shrink so that less blood will leak out.
Tiny cells in the blood called platelets stick together around the wound to patch the leak.
Blood proteins, platelets, calcium and other tissue factors reach together and form what is known as a clot. The clot acts like a net to reinforce wound closure.
When certain blood clotting factors are deficient or missing, the blood does not clot as it should, and it takes longer for a clot to form and for bleeding to stop. Treatment is available that involves infusing the missing factors so that the blood will clot more effectively.
References
- National Hemophilia Foundation. What Is A Bleeding Disorder? http://www.wfh.org/2/1/BACKUP/BACKUP/1_1_3_HistoryHemophilia.htm. Accesed June 8, 2011.
- World Federation of Hemophilia. What are rare clotting factor deficiencies? http://www.wfh.org/2/1/1_3_What-are-clotting-factors.htm. Accessed June 8, 2011.

