Peripheral Nervous System "SNS" Flashcards

1
Q

What is the predominant NT in the periphery?

A

ACh

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2
Q

ACh is the NT released from what nerves?

A

Somatic motor Neurons
PREganglionic sympathetic nerves
PREganglionic parasympathetic nerves
POSTganlionic parasympathetic Nerves

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3
Q

with one exception ______ is released from all sympathetic POSTganglionic nerves.

A

Norepinephrine (NE)

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4
Q

with one exception NE is released from all sympathetic POSTganglionic nerves what is the 1 exception?

A

Sweat glands

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5
Q

with one exception NE is released from all sympathetic POSTganglionic nerves. Sweat glands are the 1 exception. So what is released to sweat glands from sympathetic POSTganglionic nerves?

A

ACh

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6
Q

the Adrenal medulla is innervated by what?

A

sympathetic PREganglionic neurons.

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7
Q

the Adrenal medulla is innervated by sympathetic PREganglionic Neurons, hence ________ released from sympathetic preganglionic neurons elicits the release of hormones (notably EPi and NE) from the adrenal medulla

A

ACh

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8
Q

What are the 2 major subtypes of CHOLINERIC receptors?

A

Nicotinic

Muscarinic

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9
Q

Muscarinic receptors are found where?

A

Peripherially in tissues

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10
Q

Muscarinic receptors are found peripherally in tissues and innervated by ________ neurons?

A

Parasympathetic POSTganglionic neurons

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11
Q

Nicotinic receptors (nAChR) are found where?

A

peripherally in the motor end-plate of skeletal muscle and on cell bodies of both sympathetic and parasympathetic POSTganglionic neurons.

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12
Q

Nicotinic receptors (nAChR) are found peripherally in the motor end-plate of skeletal muscle and on cell bodies of both sympathetic and parasympathetic POSTganglionic neurons. they respond to what 2 things in a biphasic fashion.

A

ACh or ACh agonist (e.g. SCh)

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13
Q

In SMALL doses, ACh stimulates nicotinic receptors of the POSTganglionic sympathetic and parasympathetic neurons as well as nicotinic receptors of the skeletal muscle end plate to cause what?

A

Depolarization

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14
Q

In HIGh doses or w/ prolonged exposure, the nAChR becomes desensitized to SCh and the postsynaptic membrane becomes non-excitable; this is called what?

A

Phase II block

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15
Q

What Nerve fiber adjust skeletal muscle force and length

A

A-Alpha

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16
Q

What sensory Nerve fiber(s) are responsible for proprioception

A

A-Alpha

A-Beta

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17
Q

What Nerve fiber carry sensations of throbbing pain and temp

A

dC (C-fibers)

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18
Q

What Nerve fiber carry sensations of sharp, prickling pain, and temperature?

A

A-delta

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19
Q

Sympathetic and Parasympahetic preganglionic neurons and what fibers?

A

B fibers

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20
Q

POST ganglionic sympathetic neurons are what nerve fibers?

A

C-fibers (sC)

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21
Q

______ nerves conduct action potentials at greater velocities the ____ nerves

A

Myelinated

unmyelinated

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22
Q

Nerves with ____ diameters conduct action potentials at greater velocities than nerves w/ _____ diameters.

A

Larger

Smaller

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23
Q

Question:

what neurons conduct action potentials faster, those with larger diameters or those with smaller diameters?

A

Large diameters conduct action potentials at greater speeds

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24
Q

The sympathetic outflow is also termed what?

A

thoracolumbar outflow

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25
Q

Cardioaccelerator fibers arise from what segments?

A

T1-T4

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26
Q

The Sympathetic outflow arises from what segments?

A

T1-L2
or some say
T1-L3
AKA the thoracolumbar

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27
Q

S/S of horner’s syndrome are due to what?

A

stellate ganglion blockade

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28
Q

What are the S/S of hornet’s syndrome?

A
ipsilateral:
Miosis
Ptosis
enophthalmos
FLUSHING
increased skin temp
Anhydrosis
NASAL CONGESTION

** CAPITAL S/S above are r/t CV

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29
Q

ALL sympathetic PREganglionic fiber pass through what?

A

White rami

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30
Q

Some but not all sympathetic POSTganglionic fibers pass through what>?

A

Gray Rami

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31
Q

PREganglionic white rami are distributed to spinal nerves arising from what segments (levels)

A

T1-L2

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32
Q

Gray Rami are distributed to what spinal nerves from the ganglia

A

ALL

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33
Q

White or Gray?? rami allow coordinated, mass discharge of the sympathetic Nervous system?

A

Gray

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34
Q

After NE diffuses away from the receptor it attached to; it is removed from the synaptic cleft by what 3 ways?

A

1) reuptake (80%)
2) Metabolism by MOA in synaptic cleft
3) Diffusion into plasma where metabolized by COMT

35
Q

SNS response:

Heart BETA-1

A
Increased Chronotropy (SA node)
Increased dromotrophy (AV node)
Increased Inotrophy (Muscle fibers)
36
Q

SNS response:

Arterial Blood vessels Alpha -1 (most systemic vessels)

A

Vasoconstriction (increased SVR)

37
Q

SNS response:

Arterial Blood vessels Beta-2 (skeletal muscle vessles)

A

Vasodilation (decreased SVR)

38
Q

SNS response:

Veins Alpha-1

A

Vasoconstriction (Increased Preload)

39
Q

SNS response:

Lungs Beta-2

A
Bronchodilation (Bronchiolar muscle)
Increased Secretions (secretary glands)
40
Q

SNS response:

Kidney Beta-1

A

Increased renin

41
Q

SNS response:

Liver Beta-2

A

Glycogenolysis
Gluconeogenesis
(AKA increased BGL)

42
Q

SNS response:

Uterus Beta-2

A

relaxation

43
Q

SNS response:

Na-K+ pump Beta-2

A

Stimulates Na+-K+ pump. decrease plasma K+

44
Q

Beta-2 stimulation promotes what with BGL and why?

A

hyperglycemia

- 2ndary to glycogenolysis and gluconeogenesis

45
Q

Beta-2 stimulation promotes what to K+ levels and why?

A

Hypokalemia

- drives K+ into cells

46
Q

What are the side effects of Beta-2 Agonist ritodrine (Yutopar)

A

Hyperglycemia
Hypokalemia
tachycardia

47
Q

what are 2 important stimuli for aldosterone release?

A

Angitension II

High Serum K+

48
Q

What receptors does it work on? and give trade name.

Phenylephrine

A
Alpha 1 (minimally alpha 2)
neosynephrine
49
Q

What receptors does it work on? and give trade name.

Clonidine

A
Alpha 2 (minimally Alpha 1)
Catapress
50
Q

What receptors does it work on? and give trade name.

isoproterrnol

A

Beta 1 and Bet 2

isuprel

51
Q

What receptors does it work on? and give trade name.

Dobutamine

A
Beta 1 (minimal alpha 1)
Dobutrex
52
Q

What receptors does it work on? and give trade name.

Turbutaline

A
Beta 2 (minimal beta 1)
Brethine
53
Q

What receptors does it work on? and give trade name.

Ritidrine

A
Beta 2 (minimal Beta 1)
Yutopar
54
Q

What receptors does it work on? and give trade name.

Epinephrine

A

Alpha 1 and 2 and Beta 1 and 2 (alpha 2 the least)

Adrenalin

55
Q

What receptors does it work on? and give trade name.

Norepinephrine

A

Alpha 1 and 2 and beta 1

Levophed

56
Q

What receptors does it work on? and give trade name.

Dopamine

A

Alpha 1 and 2, and Beta 1 (minimal beta 2)

Inotropin

57
Q

What receptors does it work on? and give trade name.

Ephedrine

A

alpha 1 and 2 and beta 1 and 2

Ephedrine

58
Q

Diastolic arterial Blood pressure changes in the same direction as what?

A

SVR
- decreases in Diastolic BP and possibly also MAP with low dose epinephrine are attributed to beta 2 mediated vasodilation (beta 2 mediated decrease in SVR)

59
Q

What receptors does it block? and give trade name.

Phenoxybenzamine

A

Alpha 1 and 2 (more 1)

Dibenzyline

60
Q

What receptors does it block? and give trade name.

Prazosin

A

Alpha 1

Minipress

61
Q

What receptors does it block? and give trade name.

timolol

A

Beta 1 and 2 (slightly more 2)

Blocardren

62
Q

What receptors does it block? and give trade name.

Esmolol

A

Beta 1 and 2 (know 1 more)

Brevibloc

63
Q

What receptors does it block? and give trade name.

Labetalol

A

Alpha 1 and beta 1 and 2

Normadyne

64
Q

Phenoxybenzamie is a long acting non-selective alpha-adrenergic Antagonist. it is used to control blood pressure in patients with what d/o

A

pheochromocytoma

65
Q

Phentolamine (regitine) in a (selective or Nonselective) alpha adrenergic antagonist?

A

nonselective (alpha 1 and alpha 2)

66
Q

Yohimbine is a selective alpha 2 adrenergic antagonist used to treat what?

A

impotence

67
Q

Unlike non-selective Alpha- blockers Prazosin (a selective alpha 1 adrenergic antagonist) lowers blood pressure without increasing the release of what? from postganglionic sympathetic nerve terminals b/c it does not block alpha 2

A

Norepinephrine

68
Q

Non-selective Beta 2 agonist such as propranolol are generally avoided in what patients? and why?

A

pts w/ irritable airways (asthma)

- b/c beta 2 blockade can induce bronchospasms)

69
Q

Esmolol a competative beta 1 antagonist is very short acting b/c it is metabolized how

A

in the plasma by non-selective esterases of the RBC

70
Q

Esmolol is used to treat what in the OR?

A
  • SVT
  • HTN
  • Blunt CV reflexes to intubation
  • controlled hypotension
71
Q

Labetolol decreases what 3 things

A
  • HR
  • Myocardial contractility
  • SVR
72
Q

For labetalol the beta to alpha block is what after IV administration

A

7:1

73
Q

What are treatments for excessive myocardial depression from Beta Antagonist excess

A
Atropine (7mcg/kg)
Dobutamine
Calcium Chloride ( 250-1,000mg IV)
Glucagon (1-10 mg)
Pacemaker
  • ** don’t need to memorize doses
    • don’t give dopamine
74
Q

what should be blocked first with a pt with a pheochromocytoma and why?

A
  • Alpha prior to Beta

- Beta receptor blockade without alpha receptor blockade can cause heart failure

75
Q

what is up regulation?

A

chronic exposure pf receptors to a competitive antagonist cause an increase in the number of it’s receptors

76
Q

What drugs commonly cause up regulation

A

Beta blockers

77
Q

what would happen to a pt who was abruptly d/c from their beta blockers?

A

the response would be tachycardia and increased contractility b/c of increased # of beta 1 receptors. which could lead to MI if pt has CAD

78
Q

Case scenario Questions.
After injecting a LA into the intrathecal space, you determine that the level of sensory block is T4
A) what is the anatomical landmark for T4?
B) Do you expect that this patient will develop Tachycardia during the case? explain your answer.

A

A) T4 dermatome = nipple
B) No, Autonomic (sympathetic block)is 2-6 dermatome segments higher than sensory block. Since sympathetic outflow from T1-T4 include the cardiac accelerator fibers, blockade of this segment would prevent tachycardia ( watch for bradycardia)

79
Q

Case scenario Questions.
Your pt has been treated w/ an MAO inhibitor for depression. General anesthetic is planned for a ruptured appendix.
A) what drug will you most avoid?
B) what other drug might you also want to avoid using?

A

A) demerol (meperidine)

B) Ephedrine (indirect acting)

80
Q

Case scenario Questions.
Your OB pt is given ritodrine fir her premature labor.
A) what kind of drug is Ritodrine?
B) What are the 3 SE of Ritodrine?

A

A) Tocolytic, meaning it relaxes the uterus, More specifically a beta 2 agonist
B) Hyperglycemia, Hypokalemia, Tachycardia

81
Q

Case scenario Questions.
Your OB pt becomes hypotensive and needs a vasopressor.
A) what agents my be best?
B) why?

A

A) Ephredrine or Phenylephrine

B) Ephedrine does not appreciably decrease uterine blood flow

82
Q

Case scenario Questions.
Your pt has severe asthma
A) what adrenergic agents would you avoid using in this pt?

A

Beta 2 blockers, (propranolol and Labetalol) also avoid histamine releasing drugs such as trimethaphan, d-tubocrarine, atracurium, mivacurium

83
Q

Case scenario Questions.
The pt is beta blocked to treat HTN. The anesthesiologist terminates the beta blocker therapy 48 hours before sx. Preoperatively, the pt shows tachycardia, HTN, and ECG shows signs of MI.
A) what explains the tachycardia and ECG signs of MI?
B) you probably would treat this problem with what agent?
C) Should beta blocker therapy be d/c’d prior to surgery?

A

A) Beta receptor upregulation, once withdrawn from beta blocker the unblocked heart is hypersensitive to catecholamines
B) Esmolol, B/c it’s short acting and titrating to desired bp is fairly easy.
C) No!!

84
Q

Case scenario Questions.
Your pt is on a high dose beta blocker.
A) you would avoid using what intravenous General anesthetic. Why?

A

A) Ketamine, stimulates the SNS, which will constrict blood vessels and increase SVR and after load. the beta blocked heart may not tolerate the increased after load and heart failure may ensue