Autonomic Nervous Sys Flashcards
(133 cards)
1
Q
Which autonomic division have short preganglionic fibers?
A
sympathetic
2
Q
Which autonomic division have long preganglionic fibers?
A
parasympathetic
3
Q
What is considered as a giant ganglion that does not have post-ganglionic fibers?
A
adrenal medulla
4
Q
What does adrenal medulla release into bloodstream?
A
E, NE, dopamine and peptides
5
Q
Cell bodies of sympathetic pre-ganglionic neurons are located where in throaco-lumbar spinal nerves?
A
intermediolateral cell column
6
Q
Which rami do sympathetic fibers exit from spinal nerves?
A
ventral
7
Q
What are the 3 modes of innervation of sympathetic division?
A
1) pre –> paravertebral ganglia or prevertebral ganglia –> post
2) pre –> specialized ganglia –> target organs
3) pre –> adrenal medulla
8
Q
What are the specialized ganglia?
A
1) superior cervical
2) celiac
3) superior mesenteric
4) inferior mesenteric
9
Q
What are the two outflows of parasympathetic division?
A
1) cranial
2) sacral
10
Q
What cranial nerves do preganglionic fibers travel along?
A
1) oculomotor
2) facial
3) glossopharyngeal
4) vagus
11
Q
What four organs do sacral outflow provide to?
A
1) bladder
2) descending large intestine
3) rectum
4) genitalia
12
Q
What is a system of ganglia sandwiched between layers of the gut and connected by a dense meshwork of nerve fibers?
A
enteric nervous sys
13
Q
Which plexus controls GI tract motility and is located in smooth muscle layer?
A
myenteric plexus
14
Q
Which plexus controls secretions and ion and fluid transport?
A
submucosal plexus
15
Q
What does dual innervation mean?
A
most organs receive both sympathetic and parasympathetic innervation and actions are controlled by both division
16
Q
Which organs have sympathetic innervation only (5)?
A
1) hair follicles
2) thermoregulatory sweat glands
3) liver
4) adrenal glands
5) kidneys
17
Q
Which organ has both divisions producing similar effects?
A
salivary glands
18
Q
Which nerve fibers release Ach?
A
1) all somatic nerves
2) all preganglionic fibers in ANS
3) parasympathetic post-ganglionic
19
Q
Which nerve fibers are adrenergic or dopaminergic?
A
sympathetic post-ganglionic
20
Q
What type of receptors do sweat glands have?
A
muscarinic that responds to Ach and is regulated by sympathetic post-ganglionic fibers
21
Q
What are the four steps to neurotransmission?
A
1) synthesis
2) storage
3) release
4) termination of action
22
Q
What mediates the uptake of choline?
A
choline transporter (CHT)
23
Q
What mediates the conjugation step in synthesis of Ach?
A
choline acetyltransferase (ChAT) acetyl-CoA + Choline --> Ach
24
Q
What provides storage of Ach once it’s been synthesized?
A
vesicle-associated transporter (VAT)
25
What are the steps to release Ach from nerve terminal?
1) depolarization of nerve terminal
2) voltage-dependent Ca2+ entry
3) Ca2+ - calmodulin association with vesicle-associated membrane protein (VAMP) and synaptosome-associated proteins (SNAP)
4) vesicle fuses and Ach releases via exocytosis
26
What are the steps to termination of action in the neurotransmission of Ach?
1) rapid hydrolysis of Ach by AchE
| 2) choline is re-uptake
27
Which drug inhibits the synthesis step of Ach? What is its mechanism?
Hemicholiniums --> blocks uptake of choline by inhibiting choline transporter
28
What drug inhibits the storage of Ach? What is its mechanism?
Vesamicol --> inhibits vesicle-associated transporter
29
What drug inhibits the release of Ach? What is its mechanism?
Botulinum toxin --> blocks VAMP and SNAP
30
What drug inhibits the termination of action in the neurotransmission of Ach?
AchE inhibitors
31
Which steps of cholinergic neurotransmission the most important and if inhibited will have severe consequences?
synthesis and storage because Ach is needed all over the body, especially in NMJ and also all pre-ganglionic fibers of ANS require Ach
32
What are the two types of cholinergic receptors?
1) muscarinic
| 2) nicotinic
33
Which cholinergic receptor is a G-protein and which is a transmembrane ion channel?
muscarinic --> G-protein
| nicotinic --> ion channel
34
What are the different subunits of ion channel and where does Ach bind?
5 subunits --> 2 alpha, beta, delta, gamma
| Ach binds to both alpha subunits
35
Where are M3 receptors located in the eye?
1) sphincter muscle
| 2) ciliary muscle
36
What effects does the activation of M3 receptors have on the eye?
sphincter muscle --> pupil constriction
| ciliary muscle --> decreases angle and increases drainage of aqueous humour
37
What type of receptors are most predominate in the heart?
M2
38
What type of G protein is M2?
inhibitory
39
What's the effect on SA node with activation of M2?
decrease heart rate
40
What's the effect on AV node with activation of M2?
decrease conduction velocity
41
What's the effect on atrial muscle with activation of M2?
decrease atrial contraction
42
What's the effect on ventricular muscle with activation of M2?
decrease ventricular contraction (weak effect)
43
What type of receptors are located in the lungs?
M3
44
What effect does activation of M3 receptors have on bronchi and bronchioles?
contraction --> bronchospasm
45
What effect does activation of M3 receptors have on bronchilar submucosal glands?
secretion --> narrow lumen
46
What type of manipulation to M3 can be done to alleviate symptoms of a patient with asthma?
M3 antagonists
47
What type of receptors are located in stomach? What effect does it have when activated?
M3 --> motility, cramps
48
What type of receptors are located in glands of GI tract? What effect does it have when activated?
M1 --> secretion
49
What type of receptors are located in intestine and what effect does it have when activated?
M3 --> contraction - diarrhea, involuntary defecation
50
What type of receptors are located in the bladder and what are the effects when activated?
M3 --> voiding, urinary incontinence
1) contracts detrusor m
2) peristaltic urethral contraction
3) inhibits external sphincter
51
What's the significance of vascular smooth muscle innervation?
these muscles receive two sources of innervation:
1) perivascular nerves
2) endothelial cells
52
What effect do M3 receptors have on intact endothelium?
production of endothelium-derviced relaxing factor --> vasodilation
53
What effect do M3 receptors have on damaged endothelium?
None. Instead NT will act on M3 receptors on vascular smooth muscle cells
54
What effect do M3 receptors have on vascular smooth muscle?
vasoconstriction
55
What type of receptors are in glands and sphincters?
M3
56
What effects do M3R have on glands?
secretion --> sweat
| salivation and lacrimation
57
What effects do M3R have on sphincters?
mostly relaxation, except in lower esophageal sphincter ---> contraction
58
What type of G protein is M1?
Gq
59
What type of G protein is M2?
Gi
60
What type of G protein is M3?
Gq
61
Describe the mechanism of Gq
phospholipase C --> PIP2 --> IP3 + DAG --> incr. Ca2+ + incr PKC
62
Describe the mechanism of Gi
decr adenlyl cyclase --> decr cAMP --> decr PKA
63
Where are nicotinic receptors located?
1) all autonomic ganglia
2) adrenal medulla
3) NMJ
64
What is the rate-limiting step of catechnolamine synthesis?
tyrosine hydroxylase
| Tyr --> DOPA
65
What drug can inhibit tyrosine hydroxylase?
Metyrosine
66
What is the final product in most sympathetic post ganglionic neurons?
NE
67
What is the final product in adrenal medulla?
E
68
What is the final product in dopaminergic neurons?
dopamine
69
What is the alternative pathway in synthesis of NE?
Tyramine --> NE
70
What effect does increased NE have on the body?
hypertension
71
What protein facilitate transport of dopamine in neurons?
VMAT (vesicular monoamine transporter)
72
What drug can inhibit the storage step in catecholamine synthesis?
Reserpine
73
What other practical use does reserpine have besides inhibiting VMAT?
used to treat hypertension
74
How is NE released from neurons?
similar to Ach release (exocytosis)
75
What drug can inhibit the release step of catecholamine synthesis? What does it target?
Bretylium --> inhibits VAMP
76
What are the different actions that can be taken in termination of action of catecholamine?
1) diffusion (synapse or circulation)
2) autoreceptor
3) re-uptake
77
What are different ways to re-uptake NE?
1) re-uptake via NE transporter
| 2) metabolize by MAO (mitochondrial monoamine oxidase)
78
What can happen when MAO is inhibited?
increase NE that can lead to hypertension
79
What type of G protein does alpha-1 receptors have?
Gq
80
What type of G protein does alpha-2 receptors have?
Gi
81
What type of G protein does beta-1&2 receptors have?
Gs
82
Which receptors have Gq?
alpha-1, M1, M3, H1, V1
83
Which receptors have Gs?
beta-1&2, D1, H2, V2
84
Which receptors have Gi?
M2, alpha-2, D2
85
What autonomic receptor is found in radial muscle of the eye?
alpha-1
86
What autonomic receptor is found in sphincter muscle of the eye?
M3
87
What autonomic receptor is found in ciliary muscle of the eye?
M3 and beta-2
88
What autonomic receptor is found in ciliary body epithelium?
beta-1 & 2
89
Where are alpha-1 receptors located?
1) radial muscle
2) arterioles
3) veins
4) liver
5) male sex organ (vas deferens)
6) bladder trigone and internal sphincter
90
What action does alpha-1 receptor have on radial muscle of the eye?
contraction --> dilate pupils
91
What action does alpha-1 receptor have on arterioles?
contraction --> increase TPR
92
What action does alpha-1 receptor have on veins?
contraction --> increase venous return
93
What action does alpha-1 receptor have on liver?
increase glycogenolysis --> increase glucose
94
What action does alpha-1 receptor have on male sex organ?
vas deferens --> ejaculation
95
What action does alpha-1 receptor have on bladder trigone and internal sphincter?
contraction --> urinary retention
96
Where are dopaminergic receptors found (3)?
vascular beds --> renal, mesenteric, coronary vasculature
97
What is the action of dopaminergic receptors?
vasodilation
98
What actions do dopaminergic receptors have on kidneys?
increases glomerular filtration rate, renal blood flow and Na+ excretion
99
What autonomic receptor is responsible for increase production of aqueous humour by ciliary body epithelium?
beta-1 & 2
100
Where are alpha-2 adrenoceptors found?
1) prejunctional nerve terminal
2) platelets
3) pancreas
101
What action does alpha-2 have on prejunctional nerve terminal?
decrease terminal release and NE synthesis
102
What action does alpha-2 have on platelets?
aggregation
103
What action does alpha-2 have on pancreas?
decrease insulin secretion
104
Where are beta-1 adrenoceptors found?
1) heart (opposite of M2)
| 2) kidney
105
What action does beta-1 have on SA node?
increase heart rate
106
What action does beta-1 have on AV node?
increase conduction velocity
107
What action does beta-1 have on atrial and ventricular muscle?
1) incr force of contraction
2) incr conduction velocity
3) incr cardiac output
4) incr O2 consumption
108
What action does beta-1 have on HIs-Purkinje?
increase automaticity and conduction velocity
109
What action does beta-1 have on kidneys?
increase renin release (result in increase blood pressure)
110
Where are beta-2 adrenoceptors found?
1) blood vessels
2) uterus
3) bronchioles
4) skeletal muscles
5) liver
6) pancreas
111
What action does beta-2 have on blood vessels?
vasodilation (opposite of alpha-1)
112
What action does beta-2 have on uterus?
relaxation
113
What action does beta-2 have on bronchioles?
dilation (opposite of M3)
114
What action does beta-2 have on skeletal muscles?
incr glycogenolysis
115
What action does beta-2 have on liver?
incr glycogenolysis
116
What action does beta-2 have on pancreas?
incr insulin secretion (opposite of alpha-2)
117
Alpha-1 in the bladder is mainly located ...
blood vessels
118
Alpha-1 in the bladder has little effect on ...
detrusor muscle
119
Alpha-1 in the bladder is significant on ....
trigone/ internal sphincter --> urinary retention
120
Presynaptic receptors whose ligands are the same as the NTs released by that nerve terminal
autoreceptors
121
the transmitter affects the nerve terminals from which it is being released
homotropic interactions (autoinhibitory feedback)
122
What type of autonomic receptor is located in sympathetic neuron and acting as an autoreceptor?
alpha-2
123
What type of autonomic receptor is located in parasympathetic neuron and acting as an autoreceptor?
M2
124
one NT affects the release of another via actions on heteroreceptors
heterotropic interactions
125
In heterotropic interactions, what NT can affect sympathetic neurons and their release of NT?
Ach released by parasympathetic neurons can affect the release of NE by sympathetics
126
In heterotropic interactions, what autonomic receptor is located on sympathetic neurons in order for Ach to act upon it?
M2
127
In heterotropic interactions, what NT can affect parasympathetic neurons and their release of NT?
NE released by sympathetics can affect the release of Ach by parasympathetics
128
In heterotropic interactions, what autonomic receptor is located on parasympathetic neurons in order for NE to act upon it?
alpha-2
129
What is denervation supersensitivity?
when a nerve is cut, its downstream structure becomes supersensitive and responds to a much lower dose than before
130
What are the mechanisms to denervation supersensitivity?
1) proliferation of receptors
| 2) loss of mechanisms for removal of transmitter such re-uptake
131
What clinical significance is present for denervation supersensitivity?
1) caution when withdrawing patient off certain drugs such as beta blockers
2) can be used to detect autonomic failures
132
Neurons release multiple transmitters that interact with specific receptors and produce effect both at the pre- and post- synaptic levels
cotransmission
133
What are the two main functions of autonomic nervous system?
1) assist the body in maintaining homeostasis
| 2) accommodate coordinated body responses to external stimuli
