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Alpha 1 blockers inhibit vasoconstriction normally initiated by the baroreceptor reflex upon postural change and the subsequent drop in pressure. [26] Other antihypertensive medications may also cause orthostatic hypotension, in addition to anticholinergics , dopaminergic drugs, opiates and psychoactive medications .
The hunting reaction or hunting response is a process of alternating vasoconstriction and vasodilation in extremities exposed to cold. The term Lewis reaction is used too, named after Thomas Lewis, who first described the effect in 1930. [1] Vasoconstriction occurs first to reduce heat loss, but also results in strong cooling of the extremities.
The ability of baroreflex activation therapy to reduce sympathetic nerve activity suggests a potential in the treatment of chronic heart failure, because in this condition there is often intense sympathetic activation and patients with such sympathetic activation show a markedly increased risk of fatal arrhythmias and death. [citation needed]
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation , the widening of blood vessels.
Vasocongestion is essential for sexual procreation in mammals since this is the force that causes the hardening of a penis during an erection.The same force leads to the hardening of the clitoris and vaginal lubrication during sexual arousal. [1]
Vascular resistance is the resistance that must be overcome for blood to flow through the circulatory system.The resistance offered by the systemic circulation is known as the systemic vascular resistance or may sometimes be called by another term total peripheral resistance, while the resistance caused by the pulmonary circulation is known as the pulmonary vascular resistance.
Vasospasm refers to a condition in which an arterial spasm leads to vasoconstriction. This can lead to tissue ischemia (insufficient blood flow) and tissue death . Along with physical resistance, vasospasm is a main cause of ischemia. Like physical resistance, vasospasms can occur due to atherosclerosis.
Shock is the state of insufficient blood flow to the tissues of the body as a result of problems with the circulatory system.Initial symptoms of shock may include weakness, tachycardia, hyperventilation, sweating, anxiety, and increased thirst. [1]