Physio Ch. 11, ANS

hrdcorhrvivor's version from 2017-03-06 09:13

Section 1

Question Answer
SNSfight or flight, dilation of bv, increase heart rate, inhibition of digestion
PSNSrest and digest, constriction of bv, decrease heart rate, promote digestion
autonomic reflexesmediated by hypothalamus, pons, medulla (thirst) some mediated by spinal cord (urination, defactation, erection)
dual innervationmost organs are innervated by SNs and PSNS fibers, usually antagonistic, execpt in sexual arousal in males
preganlionic neuronCNS to ganlion, divergence
ganglionlocation varies between diversions in autonomic pathways
postganglionic neruonganglion to effector
how does SNS differ from PSNS?point of orgin in CNS, location of ganglia. SNS: thoracolumbar, galglia close to spinal column. PSNS: craniosacral, ganglia close to effector
autonomic synapsepostgang. neurons end in swellings called varicosities, those lie over target membrane
NT release and terminationacetycholinesterase AChE-> breaks down ACh in synaptic cleft. monoamine oxidase MAO-> breaks down monoamine NT
NT and receptorsSNS and PSNS release ACh onto nicotinic receptors, postganglionic r=neurons of SNS release norepinephrine onto adrenergic receptors, postganglionic neurons in PSNS release ACh onto muscarinic receptors
alpha adrenergic receptorsrespond strongly to nerepinephrine weakly to epinephrine
alpha 1cause skel. muscle contrax. activation of GPCR phospholipase c, increase intracellular calcium
alpha 2SM relaxation in GI tract and decreased secretion from pancreas, decrease in cAMP
beta adrenergic receptorsaffinities to norepinepherine and epineprhine differ between subtypes, all act by increasing cAMP
beta 1equal affinity to catecholamines, increases CM contrax
beta 2greater affinity to epinephrine, relaxes SM in most tissues
beta 3greater affinity to norephinephrine, lypolysis

Section 2

Question Answer
direct antagonist and agonistsbind to receptors and mimic or block NT
indirect antagonist and agonistsact by altering secretion, reuptake, or degradation of NT
nicotinedirect agonist, binds to nicotinic receptors leads to release of dopamine
albuteroldirect agonist, acts on beta 2 receptors, used to treat asthma
curaredirect antagonist, bind to ACh nicotinic receptor, no response, muscle weakness and death
alpha blockers direct antagonist, prevents norepinephrine from binding and contricting bv, increasing flow
beta blockersdirect antagonist, decreased heart rate and bp
cocaineindirect agonist, blocks uptake of norepinephrine, keeps excitatory effect on target
acetylcholnesterase inhibitor AChEindirect antagonist, inhibits breakdown of ACh, ACh remains in synapse longer
autonomic dysreflexiaspinal cord injuries above T 5/6, acute rx to ANS overstimulation in response to things that would normally cause pain but in area where they cant feel it, huge spike in bp, severe headache, flushed face