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Flashcards in Peripheral Nervous System "SNS" Deck (84):
1

What is the predominant NT in the periphery?

ACh

2

ACh is the NT released from what nerves?

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

3

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

Norepinephrine (NE)

4

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

Sweat glands

5

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?

ACh

6

the Adrenal medulla is innervated by what?

sympathetic PREganglionic neurons.

7

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

ACh

8

What are the 2 major subtypes of CHOLINERIC receptors?

Nicotinic
Muscarinic

9

Muscarinic receptors are found where?

Peripherially in tissues

10

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

Parasympathetic POSTganglionic neurons

11

Nicotinic receptors (nAChR) are found where?

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

12

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.

ACh or ACh agonist (e.g. SCh)

13

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?

Depolarization

14

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

Phase II block

15

What Nerve fiber adjust skeletal muscle force and length

A-Alpha

16

What sensory Nerve fiber(s) are responsible for proprioception

A-Alpha
A-Beta

17

What Nerve fiber carry sensations of throbbing pain and temp

dC (C-fibers)

18

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

A-delta

19

Sympathetic and Parasympahetic preganglionic neurons and what fibers?

B fibers

20

POST ganglionic sympathetic neurons are what nerve fibers?

C-fibers (sC)

21

______ nerves conduct action potentials at greater velocities the ____ nerves

Myelinated
unmyelinated

22

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

Larger
Smaller

23

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

Large diameters conduct action potentials at greater speeds

24

The sympathetic outflow is also termed what?

thoracolumbar outflow

25

Cardioaccelerator fibers arise from what segments?

T1-T4

26

The Sympathetic outflow arises from what segments?

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

27

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

stellate ganglion blockade

28

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

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

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

29

ALL sympathetic PREganglionic fiber pass through what?

White rami

30

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

Gray Rami

31

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

T1-L2

32

Gray Rami are distributed to what spinal nerves from the ganglia

ALL

33

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

Gray

34

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

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

35

SNS response:
Heart BETA-1

Increased Chronotropy (SA node)
Increased dromotrophy (AV node)
Increased Inotrophy (Muscle fibers)

36

SNS response:
Arterial Blood vessels Alpha -1 (most systemic vessels)

Vasoconstriction (increased SVR)

37

SNS response:
Arterial Blood vessels Beta-2 (skeletal muscle vessles)

Vasodilation (decreased SVR)

38

SNS response:
Veins Alpha-1

Vasoconstriction (Increased Preload)

39

SNS response:
Lungs Beta-2

Bronchodilation (Bronchiolar muscle)
Increased Secretions (secretary glands)

40

SNS response:
Kidney Beta-1

Increased renin

41

SNS response:
Liver Beta-2

Glycogenolysis
Gluconeogenesis
(AKA increased BGL)

42

SNS response:
Uterus Beta-2

relaxation

43

SNS response:
Na-K+ pump Beta-2

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

44

Beta-2 stimulation promotes what with BGL and why?

hyperglycemia
- 2ndary to glycogenolysis and gluconeogenesis

45

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

Hypokalemia
- drives K+ into cells

46

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

Hyperglycemia
Hypokalemia
tachycardia

47

what are 2 important stimuli for aldosterone release?

Angitension II
High Serum K+

48

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

Alpha 1 (minimally alpha 2)
neosynephrine

49

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

Alpha 2 (minimally Alpha 1)
Catapress

50

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

Beta 1 and Bet 2
isuprel

51

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

Beta 1 (minimal alpha 1)
Dobutrex

52

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

Beta 2 (minimal beta 1)
Brethine

53

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

Beta 2 (minimal Beta 1)
Yutopar

54

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

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

55

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

Alpha 1 and 2 and beta 1
Levophed

56

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

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

57

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

alpha 1 and 2 and beta 1 and 2
Ephedrine

58

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

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

What receptors does it block? and give trade name.
Phenoxybenzamine

Alpha 1 and 2 (more 1)
Dibenzyline

60

What receptors does it block? and give trade name.
Prazosin

Alpha 1
Minipress

61

What receptors does it block? and give trade name.
timolol

Beta 1 and 2 (slightly more 2)
Blocardren

62

What receptors does it block? and give trade name.
Esmolol

Beta 1 and 2 (know 1 more)
Brevibloc

63

What receptors does it block? and give trade name.
Labetalol

Alpha 1 and beta 1 and 2
Normadyne

64

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

pheochromocytoma

65

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

nonselective (alpha 1 and alpha 2)

66

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

impotence

67

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

Norepinephrine

68

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

pts w/ irritable airways (asthma)
- b/c beta 2 blockade can induce bronchospasms)

69

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

in the plasma by non-selective esterases of the RBC

70

Esmolol is used to treat what in the OR?

-SVT
- HTN
- Blunt CV reflexes to intubation
- controlled hypotension

71

Labetolol decreases what 3 things

- HR
- Myocardial contractility
- SVR

72

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

7:1

73

What are treatments for excessive myocardial depression from Beta Antagonist excess

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

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

-Alpha prior to Beta
- Beta receptor blockade without alpha receptor blockade can cause heart failure

75

what is up regulation?

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

76

What drugs commonly cause up regulation

Beta blockers

77

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

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

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) 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

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) demerol (meperidine)
B) Ephedrine (indirect acting)

80

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

81

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

A) Ephredrine or Phenylephrine
B) Ephedrine does not appreciably decrease uterine blood flow

82

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

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

83

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) 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

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

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