Definition
What is ischemia?
Ischemia is a shortfall in the blood reaching part of the body, serious enough that the tissue cannot get the oxygen and nutrients it needs or clear away its wastes. It usually happens because an artery is narrowed or blocked, most often by atherosclerotic plaque, a blood clot or an embolus, though a general failure of circulation can also cause it.
Cells starved of oxygen fall back on less efficient anaerobic metabolism, run short of energy and start to malfunction. If blood flow returns quickly, they can recover; if ischemia lasts too long, they die, and the patch of dead tissue is called an infarct. Brain cells are especially sensitive and begin to die within minutes of losing their blood supply.
In the heart, ischemia often shows up first as angina, chest pain that appears when the heart works harder than its narrowed coronary arteries can supply, which is why coronary heart disease is also called ischemic heart disease. In the brain, a short episode that clears on its own is a transient ischemic attack (TIA), while a lasting blockage causes an ischemic stroke.
Word parts
Where does the word “ischemia” come from?
- isch-
- to hold back, to restrainGreek iskhein
- -emia
- bloodGreek haima
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Terms that go with it
- InfarctionInfarction is the death of an area of tissue, called an infarct, caused by a sudden loss of its blood supply, as in a heart attack or a stroke.
- AtherosclerosisAtherosclerosis is a disease in which fatty plaque builds up inside artery walls, stiffening and narrowing the arteries and reducing blood flow.
- StrokeA stroke is a sudden loss of brain function that happens when an artery supplying the brain is blocked or bursts and bleeds.
- NecrosisNecrosis is the unplanned death of cells or tissue caused by injury, infection, toxins or loss of blood supply, and it usually triggers inflammation.
- ThrombosisThrombosis is the formation of a blood clot, called a thrombus, inside a blood vessel or the heart, where it can narrow or block the flow of blood.
- EmbolismAn embolism is a blocked blood vessel caused by an embolus, a clot or other mass carried in the bloodstream from elsewhere in the body.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- NCI Dictionary of Cancer Terms: ischemia
- NCBI MeSH: Ischemia
- MedlinePlus Medical Encyclopedia: Stable angina
- MedlinePlus: Ischemic Stroke
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