The nerve supply to a tissue, organ or part of the body. It carries motor impulses to and sensory impulses away from the part.
n. the nerve supply to an area or organ of the body, which can carry either motor impulses to the structure or sensory impulses away from it towards the brain.
An acetic-acid ester of the organic base choline, acetylcholine is one of the substances which mediates the transmission of nerve impulses from one nerve to another, or from a nerve to the organ it acts on, such as muscles. It acts on both muscarinic receptors (blocked by ATROPINE and responsible for ganglionic and parasympathetic transmission and also for sympathetic innervation of sweat glands – see under AUTONOMIC NERVOUS SYSTEM) and nicotinic receptors (responsible for the transmission of nerve impulses to muscles and blocked by curare, thus causing paralysis). Acetylcholine is rapidly destroyed by cholinesterase, an ENZYME present in the blood. ANTICHOLINERGIC drugs such as PHYSOSTIGMINE prolong the action of acetylcholine.... acetylcholine
A greatly enlarged colon that may be present at birth or develop later. It can occur in all age groups and the condition is typi?ed by severe chronic constipation. Megacolon is caused by obstruction of the colon which may be due to faulty innervation, or to psychological factors. Other causes are HIRSCHSPRUNG’S DISEASE or ULCERATIVE COLITIS. In old people the persistent use of powerful laxative drugs may cause the condition.... megacolon
(JGA) a microscopic structure within the kidney that is important in regulating blood pressure, body fluid, and electrolytes. It is situated in each nephron, between the afferent arteriole of the glomerulus and the returning distal convoluted tubule of the same nephron. The JGA consists of specialized cells within the distal tubule (the macula densa), which detect the amount of sodium chloride passing through the tubule and can secrete locally acting vasoconstrictor substances that act on the associated afferent arteriole to induce a reduction in filtration pressure (tubuloglomerular feedback). Modified cells within the afferent arterioles secrete *renin in response to a fall in perfusion pressure or feedback from the macula densa and form a central role in the renin-*angiotensin-aldosterone axis. Mesangial cells support and connect the macula densa and the specialized cells in the afferent arteriole and have sympathetic innervation, facilitating the renin response to sympathetic nervous stimulation.... juxtaglomerular apparatus
a congenital condition characterized by drooping (*ptosis) of one eyelid. On opening or moving the mouth, the droopy lid elevates momentarily, resembling a wink. It is believed to be due to an abnormal innervation of the levator muscle by the trigeminal nerve. [R. Marcus Gunn (1850–1909), British ophthalmologist]... marcus gunn jaw-winking syndrome
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