blood clotting


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blood clot·ting

(blŭd kloting)
Process in which platelets, in conjunction with clotting factors, transform blood from a liquid into a semisolid mass.
Synonym(s): blood coagulation.

blood clotting

The cascaded sequence of changes which occur when blood comes in contact with damaged tissue and which culminates in the production of a solid seal in the damaged vessel. At least 13 factors are consecutively involved in a process that culminates in the conversion of the protein fibrinogen to the fibrin that forms the main constituent of the clot. This last stage is catalyzed by the enzyme thrombin. The smooth endothelial lining of the blood vessels normally prevents clotting within the circulation, but damage to this lining may allow THROMBOSIS to occur.
Blood clottingclick for a larger image
Fig. 73 Blood clotting . The process of clotting.

blood clotting

a condition where elements in the BLOOD PLASMA change consistency from a liquid to a gel-like structure, causing a ‘clot’ to form at the site of damage. The process of clotting is complex, but can be summarized as follows:
  1. damage to the blood circulatory system causes both BLOOD PLATELETS and the BLOOD VESSELS to secrete thromboplastin (see HAEMOPHILIA).
  2. thromboplastin, in the presence of calcium ions, causes prothrombin (a globulin type of plasma protein produced in the liver when vitamin K is present) to change to thrombin (see ANTICOAGULANT).
  3. thrombin acts as an ENZYME, causing FIBRINOGEN (another type of plasma protein) to be changed to fibrin which, when it contracts, forms a mesh of fibres in which blood cells become trapped. The final result of clotting is a hard lump which can plug the damaged area (if not too large) thus preventing further loss of blood and entry of microorganisms from outside.

Patient discussion about blood clotting

Q. What causes blood clots? My father had a heart attack which was caused by a blood clot. Am I at risk for developing blood clots too? How do I prevent it from happening?

A. I found a website that checks your risks for inheriting your family's illness, including blood clots. They have a test you can do which is called "Free Risk Assessment for Thrombophilia":
http://www.dnadirect.com/patients/tests/blood_clotting/more_about/GH_Thr_Risk.jsp

Q. How can I prevent blood clots? I am 45 years old and am supposed to go on a business trip overseas. The flight itself is 12 hours long and then I have to continue traveling by bus. Could this cause me to have blood clots? If so, how can I prevent it?

A. Always walk as much as you can on the plane. Also, rotate your ankels in circles. Sometimes try to use your ankels and make the alphabet with them. Have fun..

Q. very dark blood clots @ first sight of period? At first sight of period, instead of normal rosy spotting it's brownish spotting followed by small clots.

A. totally agree with hottie, most likely that will be in normal range of variation. unless you feel some unusual pain, then you need to find medical advice. but it is also suggested for you to go to your ob-gyn doctor for a regular checkup anyway.
stay healthy always..

More discussions about blood clotting
References in periodicals archive ?
The findings offer new targets for the development of drugs to regulate blood clotting, he added.
This potential effect on blood clotting "is a theoretical concern, not yet seen," says Fitzgerald.
"It appears that these films can be formulated in such a way as to prevent any leaching of the chemicals," says Mark Meyerhoff of the University of Michigan in Ann Arbor, who has made NO-releasing materials for preventing implant-induced blood clotting. Schoenfish's work provides "a very important element to the potential practical application of this type of coating." Using NO to prevent bacterial adhesion "is really exciting," he adds.
Aspirin is known to inhibit blood clotting, so people with a tendency to form clots could take this drug to offset their risk, Goldschmidt says.
He and Zheng propose that vitamin E quinone inhibits carboxylase by binding to the site on the enzyme where vitamin K--which activates the blood clotting cascade--normally attaches.
Traditional thinking holds that the endothelial lining helps prevent blood clotting by acting as a nonstick surface.