Introduction to ANS Flashcards

1
Q

Enteric Nervous System divisions:

A

Myenteric plexus (Auerbach’s)

Submucosal plexus (Meissner’s)

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2
Q

Additional functions of enteric neurons?

A

Mechanoreceptors

Chemoreceptors

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3
Q

Substances released by excitatory enteric neurons?

A

Ach and Substance P
Serotonin, Nitric Oxide, and Neuropeptide Y
Enkephalins, dopamine, ATP

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4
Q

Substances released by inhibitory enteric neurons?

A

Dynorphin and VIP

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5
Q

Activity in the ENS is largely modulated by the?

A

Sympathetic NS

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6
Q

Ratio of pre-ganglionic to post-ganglionic fibers in ENS?

A

1:1000

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7
Q

Norepi containing ENS neurons ____?

A

Inhibit intestinal motility

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8
Q

Norepi + Neuropeptide Y containing ENS neurons ____?

A

Regulate blood flow

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9
Q

Norepi + Somatostatin containing ENS neurons ____?

A

Control intestinal secretion

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10
Q

PSNS

A
Craniosacral
Longer preganglionic fiber
1:1 or 1:2 ratio
Localized/Discrete response
Maintains Homeostasis
Ach, Nicotinic & Muscarinic receptors
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11
Q

SNS

A
Thoracolumbar
Shorter preganglionic fiber
1:20 ratio 
Generalized response
Emergency situations
NE, N & M, a&b receptors
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12
Q

Drugs that block Na channels:

A

Saxitoxin (red tide toxin)
Tetrodotoxin (puffer fish toxin)
Local anesthetics

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13
Q

Toxin that inhibits neurotransmitter release?

A

Botulinum toxin

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14
Q

What follows generalized permeability change?

A

Depolarization followed by excitatory post-synaptic potential

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15
Q

What follows selective (small ion) permeability change?

A

Hyperpolarization (K efflux) followed by Inhibitory post synaptic potential

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16
Q

Ach is degraded by?

A

Acetycholinesterase (major)

Plasma/butyryl pseudocholinesterase (non-specific)

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17
Q

NE is degraded by?

A
catechol O' methyl transferase (COMT)
monoamine oxidase (MAO)
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18
Q

COMT is found where?

A

Liver and muscle

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19
Q

Where is MAO found?

A

Mitochondria, cytoplasm, nerve terminal, liver, intestine

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20
Q

Major pathway for termination of NE action?

A

Neuronal uptake (uptake 1)

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21
Q

What is diffusion of transmitter into perisynaptic glia and the muscle?

A

Extra-neuronal uptake (uptake 2)

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22
Q

Acetyl CoA and choline rx in the cytoplasm is catalyzed by?

A

ChAT (choline acetyl transferase)

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23
Q

The rate limiting step in Acetylcholine synthesis?

A

Entry of choline in to the nerve ending

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24
Q

Maximum Ach molecules after nerve firing?

How long do they remain in the nerve terminal?

A

3 Million

1 ms

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25
Q

Rate limiting step in NE synthesis?

A

Conversion of tyrosine to DOPA by tyrosine hydroxylase

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26
Q

2 pools of norepinephrine:

A

Vesicular pool

Cytoplasmic pool

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27
Q

The only local anesthetic that causes vasoconstriction?

A

Cocaine (prevents reuptake of NE)

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28
Q

Indirectly acting sympathomimetics:

A

Tyramine and Amphetamine

Cocaine and tri-cyclic antidepressants

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29
Q

Heteroreceptor a2:

A

Parasympathetic terminal, inhibits Ach

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30
Q

Heteroreceptor M2/M4:

A

Sympathetic terminal, inhibits NE

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31
Q

Homoreceptor/autoreceptor a2:

A

Sympathetic terminal, inhibits NE

32
Q

Homoreceptor/autoreceptor M2/M4:

A

Parasympathetic terminal, inhibit Ach

33
Q

Found in heart, smooth muscles, bladder, exocrine glands; more in BRAIN; G-protein:

A

Muscarinic Receptors

34
Q

Found in NMJ, adrenal medulla, autonomic ganglia; more in SPINAL CORD; ligand-gated:

A

Nicotinic Receptors

35
Q

M1 (ganglionic):

A

Autonomic ganglia, gastric glands, CNS, gastric parietal cells, pre-synaptic sites

IP3 & DAG: muscle contraction

36
Q

M2 (Cardiac):

A

heart, smooth muscles, CN X

Decreased cAMP; bradycardia

37
Q

M3 (Glandular):

A

Glands, smooth muscles, vascular endothelium
IP3 & DAG: muscle contraction
EDRF or NO; increased cGMP; vasodilation

38
Q

M4 (CNS)

A

Inhibitor of cAMP

Inhibitory

39
Q

M5 (CNS)

A

IP3& DAG

Excitatory

40
Q

Effects of Ach on the heart:

A

Decreased Heart Rate
Decreased conduction velocity
Decreased force of contraction

41
Q

Non-innervated glandular epithelium can be activated by:

A

Direct-acting cholinomimetic agonists

42
Q

This drug inhibits uptake of choline into nerve:

A

Hemicholinium

43
Q

The MOA of most therapeutic NMJ blockers?

A

Block nicotinic cholinergic receptors at NMJ by competitive blockade

44
Q

Excitatory; found in smooth muscles, mediates mydriasis and vasoconstriction:

A

(a)1 receptor

45
Q

(b)2 receptor is responsible for:

A

Relaxation of bronchial smooth muscle
Prevention of premature contraction
Decrease vasospasm

46
Q

Receptor especially active in inducing lipolysis in lipocytes?

A

(b)3 receptor

47
Q

Affect of Ca influx in smooth muscle?

A

Inactivation of myosin light chain kinase promoting relaxation

48
Q

Affect of Ca influx in heart?

A

Increase in force of contraction

49
Q

For treatment of cardiogenic shock?

A

Dopamine1 (D1)

50
Q

Found in the neostriatum of the brain?

A

D2

51
Q

All preganglionic fibers release:

A

Ach

52
Q

B1 receptor is responsible for:

A

Inotropic effect
Chronotropic effect
Dromotropic effect
Release of renin

53
Q

Postganglionic parasympathetic fibers release:

A

Acetylcholine

54
Q

Arteriorles, vessels and heart are controlled by:

A

Sympathetic, norepinephrine

55
Q

Sympathetic postganglionic fibers to sweat glands are:

A

Muscarinic cholinergic

56
Q

Pre-ganglionic fibers to the adrenal medulla release:

A

Acetylcholine

57
Q

Sweat glands controlled adrenergically:

A

Apocrine sweat glands

58
Q

Singly innervated structure responsible for gooseflesh appearance:

A

piloerector muscles

59
Q

Dual innervated organs:

A

Heart, bronchioles, bladder, GIT, ciliary muscle of iris

60
Q

PNS is more dominant than SNS, except for:

A

Vasomotor tone

61
Q

Reflex mechanism to orthostatic hypertension?

A

Relfex tachycardia

62
Q

Vesamicol:

A

Cholinergic, inhibits transmitter storage

63
Q

Reserpine

A

Adrenergic, irreversibly inhibits transmitter storage

64
Q

Metyrosine

A

Adrenergic, block transmitter synthesis

65
Q

Botulinum toxin

A

Prevents release from cholinergic vesicles

66
Q

Tyramine, Amphetamine

A

Promote adrenergic transmitter release

67
Q

Clonidine

A

Reduces adrenergic outflow

68
Q

Dobutamine

A

Adrenergic, selective cardiac stimulation

69
Q

Phentolamine

A

Binds and inhibits alpha receptors

70
Q

Isoproterenol

A

Binds beta receptors, increases cAMP

71
Q

Propandol

A

Binds and inhibits beta receptors

72
Q

Nicotine

A

Binds and excites nicotinic receptors

73
Q

Tubocurane

A

Prevents activation of the NMJ

74
Q

Bethanechol

A

Activates muscarinic receptors

75
Q

Atropine

A

Binds and inhibts muscarinic receptors

76
Q

Neostigmine

A

Prolongs Ach and intensifies action, cannot cross BBB

77
Q

Tranylcypromine

A

Increases stores of adrenergic transmitters