Flashcards in Autonomic Nervous system Deck (40)
Loading flashcards...
1
Parts of central NS
brain
spinal cord
2
Parts of peripheral NS
autonomic NS
somatic NS
3
parts of somatic NS
sensory
motor
4
Function of ANS
maintain HOMEOSTASIS (stable internal environment with varying external conditions)
5
Pupillary light reflex is ____
unconscious, involuntary depends on amount of light entry
6
Difference between ANS vs. somatic
voluntary?
ANS = involuntary
Somatic = voluntary
7
Difference between ANS vs. somatic
Projections
ANS = diffuse projection
Somatic = specific projections
8
Difference between ANS vs. somatic
Speed of action
ANS = slow action
Somatic = rapid action
9
Difference between ANS vs. somatic
innervation
ANS = innerv smooth and cardiac muscle and gland cells
Somatic = innerv skeletal muscle
10
Difference between ANS vs. somatic
# synapses
ANS = disynaptic
Somatic = monosynaptic
11
Inputs of ANS
input to pregnaglionic neurons
1) nucleus of solitary tract (medulla)
2) other brainstem nuclei (environ stim)
3) hypothalamus (internal state)
12
output of ANS
organs
13
Subdivisions of ANS
Sympathetic
Parasympathetic
Enteric (digestion)
14
Difference between sympathetic vs. parasympathetic
Location of preganglionic neurons
symp = pregang in thoracic and lumbar cord
parasymp = pregang in brainstem and sacral cord
15
Difference between sympathetic vs. parasympathetic
location of ganglia
symp = ganglia near spinal cord
parasymp = ganglia near target organ
16
Difference between sympathetic vs. parasympathetic
ratios of pre to post ganglionic
symp = 1:10
parasymp = 1:3
17
what is ganglion
cluster of cell bodies in peripheral NS
18
Preganglionic neurotransmitter of ANS
acetylcholine
19
postganglionic neurotransmitter of ANS
--> sympathetic
Norepinephrine and epinephrine
20
postganglionic neurotransmitter of ANS
--> parasympathetic
acetylcholine
21
receptors for ANS
1) Ach (nicotinic vs. muscarinic)
2) NE (alpha vs. beta adrenergic)
22
nicotinic ACh receptor
ionotropic so NT binds and channel opens for downstream depol
23
muscarinic ACh receptor
GPCR
24
Adrenal medulla is functionally a ____
sympathetic ganglion
25
adrenal medulla innervation
preganglionic sympathetic neurons
26
what does adrenal medulla release
norepinephrine and epinephrine into blood stream
27
effects of adrenal medulla
widespread sympathomimetic effects (incr HR)
28
How does ANS affect blood pressure?
Symp = via incr NE, incr BP
Parasymp = via ACh, decr BP
29
Sympathetic NS Effect on HR and Contractile force
SA node
1) NE binds Beta-adrenergic receptor
2) incr AC, cAMP
3) incr HR due to more HCN opening (cation entry) and depol quicker to incr firing rate
4) incr contractile force (more Ca2+ enters
5) constriction of blood vessels due to Ca2+
30
Parasymp NS effect on HR and contractile force
SA node
1) ACh binds m2 ACh receptors
2) activates G protein to inhibit AC, decr cAMP
3) decr HR = less HCN channel open
4) decr contractile force = less Ca2+ entry
31
Atropine
Sympathomimetic
M2 antagonist in heart --> incr HR
32
Propanolol
Parasympathomimetic
Beta adrenergic (1 and 2) antagonist in heart, decr HR
33
Baroreceptor reflex in response to low BP
incr sympathetic ouptut
34
Baroreceptor reflex in response to high BP
increase in parasympathetic output
35
Baroreceptor mechanism (primary mechanism)
1) Baroreceptor sense pressure at aortic arch
2) if incr blood pressure, activ nucleus of solitary tract in medulla to incr glu
3) incr glu release from nearby neurons
4) incr ACh release from cardiac plexus
5) ACh binds to nicotinic ACh receptor to cause more ACh release in SA node
6) decr HR and contractile force
36
Baroreceptor 2nd mechanism
1) neurons in solitary tract also activate nearby neurons to release GABA (inhib)
2) inhib release of Glu from neurons in T1-T5 in spinal cord
3) inhib ACh release from ganglia nearby
4) inhib NE release at SA node
37
Hypothalamus control release of ___
hormones via pituitary
posterior pituitary: brain
anterior pituitary: gland
38
Effects of VASOPRESSIN on blood pressure
1) if low blood pressure detect by subfornical organ
2) release vasopressin from posterior pituitary
3) causes vasoconstriction
4) act on kidney to incr water retention
39
Effects of RENIN
1) if low blood pressure detect
2) renin released from kidney
3) downstream activ angiotensin II (vasoconstrictor)
40
