infarction(redirected from watershed infarction)
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infarction,blockage of blood circulation to a localized area or organ of the body resulting in tissue death. Infarctions commonly occur in the spleenspleen,
soft, purplish-red organ that lies under the diaphragm on the left side of the abdominal cavity. The spleen acts as a filter against foreign organisms that infect the bloodstream, and also filters out old red blood cells from the bloodstream and decomposes them.
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elastic organs used for breathing in vertebrate animals, excluding most fish, which use gills, and a few amphibian species that respire through the skin. The word is sometimes applied to the respiratory apparatus of lower animals.
..... Click the link for more information. , brainbrain,
the supervisory center of the nervous system in all vertebrates. It also serves as the site of emotions, memory, self-awareness, and thought. Anatomy and Function
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muscular organ that pumps blood to all parts of the body. The rhythmic beating of the heart is a ceaseless activity, lasting from before birth to the end of life. Anatomy and Function
The human heart is a pear-shaped structure about the size of a fist.
..... Click the link for more information. . The acute emergency known as myocardial infarction or heart attack is usually caused by a blockage in one of the coronary arteries that supply blood to the heart muscle. The blockage typically occurs when a blood clot (see thrombosisthrombosis
, obstruction of an artery or vein by a blood clot (thrombus). Arterial thrombosis is generally more serious because the supply of oxygen and nutrition to an area of the body is halted.
..... Click the link for more information. ) lodges in an area already narrowed by arteriosclerosisarteriosclerosis
, general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are frequently accompanied by accumulations inside the vessel walls of lipids, e.g.
..... Click the link for more information. ; other causes are vasospasms in the arterial walls or viral infection of the heart. Symptoms include a crushing pain in the chest radiated to either arm (more commonly the left arm), the jaw, and the neck. The pain may be experienced, particularly in women, as pain in the shoulder or stomach, instead of the chest, and in some cases there are no symptoms at all. The seriousness of the infarction is dependent upon the amount of heart muscle affected, how long the area is deprived of blood, and whether it affects the natural pacemaker of the heart, setting off arrhythmiasarrhythmia
, disturbance in the rate or rhythm of the heartbeat. Various arrhythmias can be symptoms of serious heart disorders; however, they are usually of no medical significance except in the presence of additional symptoms.
..... Click the link for more information. such as ventricular fibrillation. Death of heart muscle tissue and heart failure may result (see congestive heart failurecongestive heart failure,
inability of the heart to expel sufficient blood to keep pace with the metabolic demands of the body. In the healthy individual the heart can tolerate large increases of workload for a considerable length of time.
..... Click the link for more information. ); damage to other vital organs, including the brain, may occur if the heart is unable to pump necessary oxygen and blood to them. Confirmation of myocardial infarction is made by electrocardiographyelectrocardiography
, science of recording and interpreting the electrical activity that precedes and is a measure of the action of heart muscles. Since 1887, when Augustus Waller demonstrated the possibility of measuring such action, physicians and physiologists have recorded
..... Click the link for more information. and measurement of elevations of white blood cells and certain enzymes. Treatment of acute myocardial infarction may include first aid in the form of cardiopulmonary resuscitationcardiopulmonary resuscitation
(CPR), emergency procedure used to treat victims of cardiac and respiratory arrest. CPR can be done in a hospital with drugs and special equipment or as a first-aid technique.
..... Click the link for more information. (CPR), an emergency balloon angioplastyangioplasty
, any surgical repair of a blood vessel, especially balloon angioplasty or percutaneous transluminal coronary angioplasty, a treatment of coronary artery disease.
..... Click the link for more information. , or the administration of beta-blockersbeta-blocker
or beta-adrenergic blocking agent
, drug that reduces the symptoms connected with hypertension, cardiac arrhythmias, angina pectoris, migraine headaches, and other disorders related to the sympathetic nervous system.
..... Click the link for more information. and thrombolytic drugsthrombolytic drug
or clot-dissolving drug,
substance, such as streptokinase or tissue plasminogen activator (tPA), that causes the breakdown of blood clots (see thrombosis) that obstruct the flow of blood through the vessels.
..... Click the link for more information. (clot-dissolving drugs), such as tissue plasminogen activator. The healing of an infarction occurs through replacement of the dead tissue by scar tissue.
See also coronary artery diseasecoronary artery disease,
condition that results when the coronary arteries are narrowed or occluded, most commonly by atherosclerotic deposits of fibrous and fatty tissue. Coronary artery disease is the most common underlying cause of cardiovascular disability and death.
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