A nerve in the wall of a blood vessel which affects the diameter of the vessel.<\/p>\n
Any nerve, usually belonging to the autonomic nervous system, that controls the circulation of blood through blood vessels by its action on the muscle fibers within their walls or its action on the heart beat. The vagus nerve slows the heart and reduces its output, but sympathetic nerves increase the rate and output of the heart and increase blood pressure by causing the constriction of small blood vessels at the same time.<\/p>\n
Small nerve fibres that lie upon the walls of blood vessels and connect the muscle fibres of their middle coat with the nervous system. Through these nerves the blood vessels are retained in a state of moderate contraction. There are vasodilator nerves, through which are transmitted impulses that dilate the vessels, and, in the case of the skin vessels, produce the condition of blushing; there are also vasoconstrictor nerves which transmit impulses that constrict, or narrow, the blood vessels as occurs on exposure to cold. Various drugs produce dilatation or contraction of the blood vessels, and several of the substances produced by endocrine glands in the body have these effects: for example, adrenaline.<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
A nerve in the wall of a blood vessel which affects the diameter of the vessel. Any nerve, usually belonging to the autonomic nervous system, that controls the circulation of blood through blood vessels by its action on the muscle fibers within their walls or its action on the heart beat. The vagus nerve slows […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-102521","post","type-post","status-publish","format-standard","hentry","category-v"],"yoast_head":"\n