vasoconstriction
Quick Summary
Vasoconstriction is the narrowing of the lumen of blood vessels. This physiological process occurs in response to environmental factors like temperature, where blood vessels constrict to retain body heat when cold and widen to dissipate heat when hot.12
The width of blood vessels directly impacts blood pressure. Vasoconstrictors are substances that cause this narrowing and are used medically to treat low blood pressure. Examples include antihistamines, amphetamines, nicotine, and caffeine, which are often found in over-the-counter medications for conditions like runny noses and bloodshot eyes.2
Conversely, vasodilators cause blood vessels to relax and widen, and they are commonly used to treat high blood pressure. Angiotensin II is a potent vasoconstrictor that raises blood pressure by constricting blood vessels. Cardiovascular drugs can affect blood vessels by altering the state of contraction of their smooth muscle, either causing vasoconstriction or vasodilation.234
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