1 Kings 2:37Viewing the 1769 King James Version. Click to switch to 1611 King James Version of 1 Kings 2:37
For it shall be, that on the day thou goest out, and passest over the brook Kidron, thou shalt know for certain that thou shalt surely die: thy blood shall be upon thine own head.
A blood clot is a thickened mass in the blood formed by tiny substances called platelets. Clots form to stop bleeding, such as at the site of cut. But clots should not form when blood is moving through the body; when clots form inside blood vessels or when blood has a tendency to clot too much, serious health problems can occur.
As soon as a blood vessel wall is damaged—by a cut or similar trauma—a series of reactions normally takes place to activate platelets to stop the bleeding. Platelets are the tiny particles in the blood released into the bone marrow that gather together and form a barrier to further bleeding. Several proteins in the body are involved in the platelets clotting process. Chief among these proteins are collagen, thrombin, and von Willebrand factor. Collagen and thrombin help platelets stick together. As platelets gather at the site of injury, they change in shape from round to spiny, releasing proteins and other substances that help catch more platelets and clotting proteins. This enlarges the plug that becomes a blood clot. Formation of blood clots also is called "coagulation".
The series of reactions that cause proteins and platelets to create blood clots also are balanced by other reactions that stop the clotting process and dissolve clots after the blood vessel has healed. If this control system fails, minor blood vessel injuries can trigger clotting throughout the body. The tendency to clot too much is called "hypercoagulation". Anytime clots form inside blood vessels, they can lead to serious complications.
The formation of a clot in a blood vessels may be called thrombophlebitis. The term refers to swelling of one or more veins caused by a blood clot. Although some clots occur in the arms or small, surface blood vessels, most occur in the lower legs. When the blood clot occurs in a deep vein, it is called deep vein thrombosis, or DVT. As many as one of every 1,000 Americans develops DVT each year. The danger of DVT comes when pieces of the clot, known as emboli, break off and travel through the bloodstream to an artery.
A blood clot that blocks an artery to the brain can cause a stroke. If the clot blocks blood flow to the lungs pulmonary embolism can occur. A blood clot that blocks a coronary artery can cause a heart attack. Certain people are at higher risk for blood clots than others; surgery, some injuries, childbirth and lying or sitting still for extended periods of time put people at higher risk, as do inherited disorders. Once a person has a blood clot, he or she may have to take bloodthinning drugs to prevent clots from recurring. Men and women are at similar risk for blood clots. A recent study in Austria found that men run a higher risk of recurring blood clots than women, though the reason is unknown.