ANS Flashcards
cholinergic nerves
nerves that synthesize and release ACh as their neurotransmitter
cholinergic receptor
receptors for Ach
what are the two main types of cholinergic receptors
- nicotinic (N)
- muscarinic (M)
adrenergic nerves
nerves that synthesize and release norepinephrine as their neurotransmitter
adrenergic receptor
receptors for norepinephrine and epinephrine.
what are the two main types of adrenergic receptor
alpha and beta
autonomic division
independent of conscious thought or control
autonomic pathway consist of what type of nerve pathway
preganglionic - ganglion - postganglionic
what does the somatic pathway consist of
single motorneuron projecting from ventral horn of the spinal cord directly to the muscle
which is slower somatic or autonomic system? Why?
autonomic is slower because it has lightly myelinated or unmyelinated neurons while somatic division has myelinated axons
what are the two divisions of the autonomic nervous system
sympathetic (thoracolumbar) and parasympathetic (craniosacral)
all pre-ganglionic fibers release what neurotransmitter onto what type of receptors in the ganglia
- acetylcholine
- nicotinic receptors
postganglionic fibers of the parasympathetic division release what neurotransmitter onto what type of receptors in the target organs
- acetylcholine
- muscarinic receptors
for the most part, post-ganglionic fibers of the sympathetic division release what neurotransmitter onto what receptors in the target organs (all except those fibers that innervate sweat glands)
- norepinephrine
- adrenergic receptors
post-ganglionic fibers of the sympathetic division release what neurotransmitter into the receptors on sweat glands
acetylcholine
the adrenal medulla is a modified part of the sympathetic nervous system. Stimulation of preganglionic fiber prompts secretion of what 2 hormones
- epinephrine (adrenaline) - 80%
- norepinephrine - 20%
what gland can cause body-wide release of epinephrine and norepinephrine in an extreme emergency (adrenaline rush)
adrenal gland
post-ganglionic fibers of the sympathetic division release what neurotransmitter in the innervation of renal vasculature
dopamine
location of neuron sympathetic preganglionic cell bodies
intermediolateral cell column in the spinal cord (T1-T3)
are sympathetic preganglionic myelinated
yes
primary neurotransmitter released in sympathetic preganglionic neurons
acetylcholine
primary postsynaptic receptor recieiving neurotransmitter from sympathetic preganglionic neuron
nicotinic
location of sympathetic postganglionic cell bodies
prevertebral and paravertebral ganglia
are sympathetic postganglionic myelinated
no
what is the primary neurotransmitter that sympathetic postganglionic neurons carry
norepinephrine
primary postsynaptic receptor that recieves neurotransmitter from sympathetic postganglionic neuron
adrenergic
location of parasympathetic preganglionic neuron cell bodies
brainstem and sacral spinal cord (S2-S4)
are parasympathetic preganglionic neurons myelinated
yes
what is the primary neurotransmitter carried in parasympathetic preganglionic neurons
acetylcholine
what is the primary postsynaptic receptor that receives neurotransmitter from parasympathetic preganglionic neurons
nicotinic
location of parasympathetic postganglionic neuron cell bodies
terminal ganglia in or near target organ
are parasympathetic postganglionic neurons myelinated
no
primary neurotransmitter carried in parasympathetic postganglionic neurons
acetylcholine
primary postsynaptic receptor that recieves neurotransmitter from parasympathetic postganglionic neurons
muscarinic
what neurotransmitters does the adrenal medulla secrete as part of the sympathetic system
- epinephrine
- norepinephrine
- dopamine
preganglionic and postganglion nerve fibers of the parasympathetic system secrete what neurotransmitter
Ach
how is acetylcholine synthesized
from Acetyl CoA and choline by choline acetyl transferase (Chat)
sythesis of norepinephrine
- tyrosine enters nerve terminal
- converted to DOPA
- DOPA converted to dopamine
- dopamine converted to norepinephrine
what are the subtypes of adrenergic receptors in the synaptic cleft that norepinephrine acts on
alpha and beta
after release into the synaptic cleft, how is norepinephrine taken up by the presynaptic vesicle
- uptake by active pump mechanism NET
cocaine and tricyclic antidepressants inhibit the uptake of what neurotransmitter into the presynaptic neuron
norepinephrine
after uptake into the presynaptic neuron, norepinephrine is metabolized by what enzymes
- COMT
- and to a lesser extent: MAO
which is more likely to be detected in the blood: acetylcholine or norepinephrine
norepinephrine
what organs have single innervation from the sympathetic nervous system
- sweat glands
- peripheral blood vessels
- hair follicles
- brown adipose tissue
- adrenal medulla
- kidney
for organs innervated by both PNS and SNS, what determines the net effect on that organ
ratio of PNS/SNS
visceral sensory and autonomic neurons participate in what function that enables defecation and micturition
visceral reflex arc
implications for dual innervation of SNS and PNS: reciprocal effects
one system inhibits while the other stimulates activity of the target organ
- provides fine control of organ function
- ex: control of HR and intestinal motility
implications for dual innervation of SNS and PNS: cooperative effects. give an example
- promote same goal
- salivary gland secretion and male sexual response
examples of reciprocal effects: list some examples of SNS fight/flight “stress” response
- inhibit digestion
- increase HR
- dilate pupil
- stimulate hepatic glycogenolysis
examples of reciprocal effects: list some examples of PNS vegetative “rest”
- enhance digestion
- slows HR
- constricts pupil
- release of insulin from pancreas
most arterioles and veins recieve only what type of innervation
sympathetic
innervation of arteries and capillaries
not innervated
most sweat glands are innervated only by
sympathetic nerves
innervation of salivary glands, lacrimal glands, and male sexual organs
SNS and PNS but activity is cooperative (not reciprocal)
list effect of cooperative effects of PNS and SNS on salivary glands
- SNS: viscous secretion
- PNS: watery secretion
list effect of cooperative effects of PNS and SNS on lacrimal glands
SNS and PNS both cause secretion
list effect of cooperative effects of PNS and SNS on sexual response (male)
- PNS: male erection
- SNS: ejaculation
during filling of the bladder, what innervation predominates
sympathetic
- causes detrusor muscle to relax
- contracts internal sphincter
- external sphincter is under voluntary control
during micturition, what innervation predominates
parasympathetic
- detrusor muscle contracts
- internal sphincter relaxes
role of hypothalamus in control of autonomic activities
intergrates autonomic, somatic, and endocrine responses that automatically accompany various emotional and behavioral states
role of medulla in control of autonomic activities
region directly responsible for autonomic output
role of autonomic reflexes in control of autonomic activities
ex: urination, defecation, and erection are integrated at spinal cord
role of amygdala in control of autonomic activities
- function: main limbic region for emotions
- stimulates sympathetic activity, especially previously learned fear-related behavior
role of reticular formation of brain stem in control of autonomic activities
most direct influence over autonomic function
