neurologic disorders
Overview of the Autonomic Nervous System
Physiology of the Autonomic Nervous System
The autonomic nervous system controls blood pressure (BP), heart rate, body temperature, weight, digestion, metabolism, fluid and electrolyte balance, sweating, urination, defecation, sexual response, and other processes. Many organs are controlled primarily by either the sympathetic or parasympathetic system, although they may receive input from both; occasionally, functions are reciprocal (eg, sympathetic input increases heart rate; parasympathetic decreases it). Thesympathetic nervous systemis catabolic; it activates fight-or-flight responses. is anabolic; it conserves and restores (see table Divisions of the Autonomic Nervous System ). Two major neurotransmitters in the autonomic nervous system are Acetylcholine:Fibers that secrete acetylcholine (cholinergic fibers) include all preganglionic fibers, all postganglionic parasympathetic fibers, and some postganglionic sympathetic fibers (those that innervate piloerectors, sweat glands, and blood vessels). Norepinephrine:Fibers that secretenorepinephrine(adrenergic fibers) include most postganglionic sympathetic fibers. Sweat glands on the palms and soles also respond to adrenergic stimulation to some degree. There are different subtypes of Norepinephrine and 