vastureaktsioone

Vastureaktsioone, also known as vasoconstriction, is a physiological process where the blood vessels narrow, reducing their diameter. This response is primarily mediated by the sympathetic nervous system and is a key component of the body's stress response. Vasoconstriction helps to redistribute blood flow to vital organs, such as the heart and brain, during periods of increased demand or stress. It is also a crucial mechanism in the regulation of blood pressure and body temperature. Vasoconstriction can be induced by various stimuli, including cold temperatures, emotional stress, and the release of certain hormones and neurotransmitters. The narrowing of blood vessels increases blood pressure and reduces blood flow to less critical areas of the body. This process is counteracted by vasodilation, where blood vessels widen to increase blood flow. Vasoconstriction is essential for maintaining homeostasis and ensuring that the body's most critical functions are adequately supplied with oxygen and nutrients. However, prolonged or excessive vasoconstriction can lead to conditions such as hypertension and peripheral vascular disease.