Question | Answer |
ans consists of motor neurons that? | innervate smooth and cardiac muscle and glands; make adjustments to ensure optimal support for body activites, subconscious |
parasympathetic division | conserves body energy, restin and digestion |
sympathetic division | fight or flight system, adjustments during exercise |
sympathetic tone (vasomotor tone) | keeps blood vessels in continual state of partial constriction, even at rest |
receives only sympathetic fibers | adrenal medulla, sweat glands, arrector pilli, kidneys, most blood vessels |
sympathetic system controls? | thermoregulatory responses to heat, release of relin from kidneys, metabolic effects (increases metabolic rate of cells, raises blood glucose, mobilizes fats for fuel) |
parasympathetic tone | slows heart, dictates normal activity levels of digestive and urinary tract; can be overridden by sympathetic division during stress |
cooperative effects | parasympathetic fibers cause erection (vasodilation); sympathetic cause ejaculation of semen and reflex contraction |
parasympathetic effects vs. sympathetic effects | para is short lived, highly localized over effectors; sympathetic is long lasting, bodywide effects |
visceral reflex arc | stimulus,sensory receptor in viscera, visceral sensory neuron, integration (progangliionic, dorsal horn, w/in wall of gi tract), efferent pathway (2 neuron chain), visceral effector, response |
referred pain? | visceral pain afferents travel aong the same pathways as somatic pain fibers, causing referred pain |
neurotransmitter released by cholinergic fibers | Acetylcholine; by all ans preganglionic axons and all parasympathetic postganglionic axons |
neurotransmitter released by adrenergic fibers | norepinephrine; by most sympathetic postgangliionic axons, except sweat glands and some blood vessels in skeletal muscles |
cholinergic receptors that bind ACh | nicotinic, muscarinic |
where are nicotinic receptors found? | motor end plates of skeletal muscle cells, all ganglionic neurons, hormone producing cells of adrenal medulla |
where are muscarinic receptors found? | on all parasympathetic target organs, all effector cells stimulated by postganglionic cholinergic fibers |
types of adrenergic receptors? | alpha and beta; effects of NE depend on which subclass of receptor predominates on the target organ |
what is atropine? | anticholinergic; blocks muscarinic receptors (used in war). prevents salivation during surgery, dialate pupils |
what is neostigmine? | inhibits acetylcholinesterase; used to treat myasthenia gravis |
effect of OTC drugs? | stimulate adrenergic receptors |
effect of beta blockers? | drugs that attach to B2 receptors to dilate lung bronchioles in asthmatics |
why is sympathetic activation long lasting? | because NE is inactivated more slowly than ACh, NE and epinephrine are released into the blood and remain until destroyed by liver |
what controls ANS functioning? | hypothalamus; subconscious cerebral input via limbic lobe connections influences hypothalamic function, cerebral cortex, reticular formation, spinal cord |
how does alcohol effect brain? | desensitizes neurotransmittor receptors |
why does ANS efficiency decline with age? | due to structural changes at preganglionic axon terminals |
why is orthostatic hypotension present in old age? | aging pressure receptors respond less to changes in blood pressure w/changes in body position and because of slowed responses by sympathetic vasoconstrictor centers |