Basic Concepts Flashcards
what NT is in what ganglion?
parasympathetic and sympathetic ganglion: both use nicotinic ACh. parasympathetic post G = muscarinic ACh. sympathetic post G = NA
three ANS divisions
sympathetic, parasympathetic, and intrinsic (enteric and intracardiac)
ANS originally regarded as what kind of system? now know it contains what components (3)?
efferent system. now: contains afferent, central and efferent components
all neres leaving CNS release? all afferent fibers are?
release ACh. are excitatory.
post ganglionic terminal axons are characterized by? def?
varicosities: swellings of the axon that occur every few microns
what accumulates in caricosities?
synaptic vesicles with NTs
two categories of receptors
ionotropic aka ligand gated ion channels. metabotropic aka linked to a G protein and second messenger system.
ionotropic receptor: produces what? aka?
production of post synpatic current = EPSP or IPSP. aka intrinsic sensor receptor, because binding site is on same molecule as channel
metabotropic receptor: structure? produces? aka?
7 TM domains or heptahelical. initiates a signal transduction cascade via G-proteins + 2ndary messengers. aka remote sensor receptors.
in peripheral autonomic nerves: which two primary NTs?
ACh for ganglia and parasympathetic. NA for sympathetic.
in peripheral autonomic nerves: 4 other small molecules?
5HT, ATP, NO, DA
in peripheral autonomic nerves: 7 neuropeptide examples?
NPY, VIP, CGRP, Substance P, galanin, SRIF, leucine and methionine enkephalin (opioid peptides)
autocoids: aka? released by? examples?
local hormones, released by neurons or target tissue in response to local signals. histamine, prostaglandins, leukotrienes, other eicosinoids, substance P, 5HT, ATP, NO
smaller vs. larger vesicles and what they contain
smaller: biogenic amines (ACh, NA) only. larger: both biogenic amines and peptides
smaller and larger vesicles both contain? which can also? regualtion?
ATP, which can also act as a co-transmitter. differentially regulated
NANC?
non-adrenergic, non-cholinergic nerves, and their responses are mediated by ATP or peptides
chemical coding means?
different autonomic nerves to different peripheral targets are often characterized by the peptide that they contain
plurichemical transmission means?
autonomic nerve releases a combo of 2+ NTs, so as to affect broad control of the target tissue
how do we get tissue specific ANS signals?
targeted innervation, presynpatic chemical coding, different post synaptic receptor subtypes
most important aspect of ANS control of viscera =?
selective and independent control of different vascular beds by sympathetic fibers. aka control of blood vessels
blood vessel layers
from in to out: tunica intima/endothelium. tunica media/smooth muscle. tunic adventitia/collagen fibers
tunica adventicia: contains?
sympathetic nerve terminals and varicosities (also contains collagen fibers)
in response to sympathetic stimualtion, blood vessel does what
smooth muscle will contract
blood vessels are under what tone?
sympathetic tone; there is very little or no parasympath. innervation of blood vessels
