A division of the autonomic or involuntary nervous system that works in general opposition to the parasympathetic division (q.v.). Many of the sympathetic functions are local, specific, and involve secretion of acetylcholine, like any other of your normal nerves...stimulating or suppressing a specific muscle, gland, or whatever. A certain number of these nerves, however, unlike any others in the body, secrete epinephrine (adrenalin) and norepinephrine (noradrenalin). These are called adrenergic.