Peripheral Nervous System Flashcards

(72 cards)

1
Q

What are the 2 divisions of the peripheral nervous system?

A
  1. Somatic

2. Autonomic - Parasympathetic & Sympathetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where do the autonomic preganglionic neurons synapse with the postganglionic neurons?

A

At the autonomic ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is the adrenal medulla innervated?

A

Preganglionic sympathetic neurons - nictoninc - Ach - Epi, NE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the predominant NT of the periphery?

A

Ach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name the receptor & NT that is released:
Preganglionic parasympathetic
Postganglionic parasympathetic
Preganglionic sympathetic
Postganglionic sympathetic
Preganglionic sympathetic to adrenal medulla
Postganglionic sympathetic to sweat glands - muscarinic, Ach
Motor neuron

A

Preganglionic parasympathetic - nicotinic, Ach
Postganglionic parasympathetic - muscarinic, Ach
Preganglionic sympathetic - nicotinic, Ach
Postganglionic sympathetic - adrenergic, NE
Preganglionic sympathetic to adrenal medulla - nicotinic, Ach
Postganglionic sympathetic to sweat glands - muscarinic, Ach
Somatic motor neuron - nicotinic, Ach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name 3 places nicotinic receptors are found.

A
  1. Autonomic ganglia
  2. Cells of the adrenal medulla
  3. Motor end-plate of skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name the 2 types of cholinergic receptors.

A
  1. Muscarinic

2. Nicotinic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

List the fiber types from LARGEST diameter to SMALLEST diameter (FASTEST to SLOWEST).

A
A-alpha
A-beta
A-gamma
A-delta
B
sC
dC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which fibers are myelinated? Unmyelinated?

A

Myelinated: A-alpha, A-beta, A-gamma, A-delta, B
Unmyelinated: sC, dC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A-alpha Fibers

A

Motor & Sensory
Muscle length & force
Proprioception
Somatic motor neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A-beta Fibers

A

Motor & Sensory
Touch & pressure
Proprioception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

A-gamma Fibers

A

Motor only

Skeletal muscle tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A-delta Fibers

A

Sensory only

Pain, temp, & touch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

B Fibers

A

Preganglionic autonomic neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

sC Fibers

A

Postganglionic sympathetic neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

dC Fibers

A

Sensory only

Pain, temp, & touch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The sympathetic, or __________, nervous system outflow arises from what segments?

A

Thoracolumbar

T1 to L2or3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where dos most preganglionic sympathetic neurons synapse with postganglionic neurons?

A

Paravertebral ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The stellate ganglion is formed by what to ganglia?

A

Inferior cervical ganglia
First thoracic ganglia
*In 80% of people, these 2 ganglia are fused
If you block — Horner’s syndrome - miosis, ptosis, anhydrosis on the IPSILATERAL side
Interscalene or supraclavicular blocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Sympathetic preganglionic neurons arise in the ___________ and pass out of the spinal cord via the ___________ root.

A
Intermediolateral horn of the spinal cord 
Anterior root (SNS stimulation = efferent/motor)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the fate of sympathetic preganglionic neurons arising in the intermediolateral horn of the spinal cord.

A

Start: Intermediolateral horn of the spinal cord
Exit: anterior root
ALL PREganglionic neurons pass through the WHITE rami on their way to the paravertebral ganglia
3 fates:
1. Synapse in the paravertebral ganglia…then the POSTganglionic neurons pass through the GRAY rami to reach the spinal nerve
2. Ascend or descend prior to synapse
3. Synapse in the peripheral ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Preganglionic white rami are distributed to spinal nerves arising from ____. Postganglionic gray rami are distributed to ___ spinal nerves from the ganglia.

A

T1-L2
ALL
*Gray rami allow coordinated, mass discharge of the SNS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens when presynaptic alpha-2 receptors are stimulated by NE or any other drug with alpha-2 receptor agonist activity?

A

The synthesis and release of NE is DECREASED

Negative feedback

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the formation of NE and Epi.

A

Tyrosine from bloodstream to nerve terminal - Dopa - Dopamine - presynaptic vesicle - NE - adrenal medulla - Epi
*Adrenal medulla pool - 80% Epi, 20% NE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Detail the termination of NE.
1st step is diffusion away from the receptors 80% reuptake into the presynaptic nerve terminal MAO found in the synaptic cleft COMT found in the bloodstream
26
Where are alpha-2 receptors found? What are their actions at these 3 sites?
1. Sympathetic postganglionic, presynaptic nerve varicosities - inhibition of NE synthesis and release 2. Sympathetic postganglionic, postsynaptic receptors in the brainstem - inhibition of SNS outflow 3. Sympathetic postganglionic, postsynaptic receptors in the substantia gelatinosa - analgesia
27
Beta-2 receptor stimulation is inhibitory in what 2 places?
1. Lungs 2. Uterus * Stimulation of beta-2 receptors in smooth muscle is INHIBITORY
28
What 2 side effects of beta-2 receptor stimulation should you consider?
1. Glycogenolysis and gluconeogenesis - BG will increase | 2. Na-K pump stimulation - K is driven into cell, HYPOkalemia results
29
________ receptor stimulation increases renin release and _______ receptor stimulation decreases renin release.
Increases renin release - Beta-1 | Decreases renin release - Alpha-1
30
_______ receptor stimulation increase insulin secretion and ________ receptor stimulation decreases insulin secretion.
Increases insulin secretion - Beta-2 | Decreases insulin secretion - Alpha-2
31
85% of the resting BP is controlled by _________.
Renin Enzyme release from juxtaglomerular cells of the afferent arteriole Converts angiotensinogen to angiotensin I
32
What 2 things does angiotensin II promote?
1. Vasoconstriction | 2. Aldosterone release
33
Name 2 important stimuli for aldosterone release.
1. Angiotensin II 2. HYPERkalemia *Less potent stimuli include ACTH & HYPOnatremia
34
What 2 things does aldosterone promote?
1. Secretion of K | 2. Retention of Na
35
``` Name the receptors that the following drugs work on. Epi NE Dopamine Ephedrine Dobutamine ```
Epi - alpha-1,2 + beta-1,2 NE - alpha-1,2 + beta-1 (NO beta-2!) Dopamine - alpha-1,2 + beta-1 + dopamine Ephedrine - alpha-1,2 + beta-1,2 (basically a weak Epi!) Dobutamine - beta-1
36
Would you notice an increase or decrease in HR with a NE infusion?
Decrease in HR - baroreceptor reflex
37
Would you notice an increase or decrease in DBP with a low-dose Epi infusion?
Decrease in DBP - beta-2-mediated vasodilation | *Beta receptors are MORE sensitive than alpha
38
Are beta or alpha receptors MORE sensitive to agonist?
Beta!
39
Would you notice an increase or decrease in DBP with an infusion of isoproterenol?
Decrease in DBP - beta-2 mediated vasodilation (no alpha-1 activity)
40
Rebound HTN is a problem with clonidine is suddenly withdrawn. Rebound HTN is mediated by what 3 things?
1. Catecholamines 2. Renin 3. Angiotensin II
41
Name 2 nonselective alpha-2 blockers. | Name 1 selective alpha-1 blocker.
``` Nonselective alpha-2 blockers 1. Phenoxybenzamine - pheo! 2. Phentolamine Selective alpha-1 blocker Prazosin ```
42
Name 2 selective beta-1 blockers. | *side notes on metabolism/elimination
1. Metoprolol 2. Atenolol (eliminated by kidneys, others BB liver) ?Esmolol (metabolized by non-selective esterases)
43
Labetolol blocks what receptors?
Alpha-1, Beta-1,2 * same as Carvedilol * alpha to beta block is 1:7 - stronger beta!
44
Caution with nonselective beta blockers in what patients?
Irritable airways (bronchoconstriction) Diabetics (hypoglycemia w/o warning signs) *Also could have HYPERkalemia
45
Reversal of beta blockade.
Glucagon 1-10 mg IV followed by 5 mg/hr IV
46
Should a patient with a pheochromocytoma be alpha or beta blocked first?
Block ALPHA prior to beta
47
Anesthetics & Beta Blockers | List from LEAST favorable to MOST favorable: opioids, halothane, enflurane, ketamine, isoflurane
``` Ketamine - least favorable Enflurane Halothane Opioids Isoflurane - most favorable ```
48
Explain down-regulation.
Chronic exposure to AGONIST DECREASED # of receptors Ex: CHF - high SNS discharge results in down regulation of beta-1 receptors
49
Explain up-regulation.
Chronic exposure to ANTAGONIST (competitive) INCREASED # of receptors Ex: beta-blocked patient - abruptly d/c meds = exaggerated response
50
The parasympathetic, or __________ nervous system outflow arises from what?
Craniosacral CN 3, 7, 9, 10 (midbrain, pons, medulla) S2-4
51
What CN transmits 3/4ths of the traffic of the parasympathetic NS?
CN X - 10 - Vagus
52
Parasympathetic NS stimulation - contraction or relaxation of the detrusor muscle?
Contraction of the detrusor muscle (bladder)
53
What is Pilocarpine?
Parasympathomimetic used to treat narrow-angle glaucoma Drainage of aqueous humor is facilitated by miosis *Another drug in this class: Bethanechol - used to treat ileus and urinary retention
54
Name 5 cholinesterase inhibitors.
1. Edrophonium 2. Neostigmine 3. Pyridostigmine 4. Physostigmine 5. Echothiophate
55
Avoid Sux and Mivacurium with which cholinesterase inhibitors?
``` Neostigmine Pyridostigmine Echothiophate *Cholinesterase inhibitors inhibit both true acetylcholinesterase and plasma cholinesterase Indirectly stimulate nicotinic receptors ```
56
Which cholinesterase inhibitor is a tertiary NOT quaternary ammonium compound and crosses the BBB?
Physostigmine | *Used to treat anticholinergic syndrome
57
Which cholinesterase inhibitor is used in the treatment of glaucoma? It is a longer acting agent.
Echothiophate
58
Which 2 cholinesterase inhibitors are used in the treatment of myasthenia gravis?
1. Neostigmine | 2. Pyridostigmine
59
What receptors are involved in mediating the responses to reversal agents?
Nicotinic and muscarinic receptors
60
How will excessive doses of acetylcholinesterase inhibitors affect NDMR? Sux?
Potentiate NDMR | Prolong Sux
61
Cholinergic Antagonists | Anticholinergic vs. Antimuscarinic
Anticholinergic: antagnoize Ach Antimuscarinic: antagonize muscarinic receptors
62
Name 3 anticholinergics.
1. Atropine 2. Scopolamine 3. Glyco
63
Which antimuscarinic least crosses the BBB and why?
Glyco | Has a charged quaternary ammonium group
64
Which cholinesterase inhibitor is used to treat anticholinergic syndrome?
Physostigmine | *Tertiary ammonium compound, non-ionized, readily crosses BBB
65
The probability of esophageal reflux __________ when the patient is given an antimuscarinic drug.
INCREASES
66
How do phosphodiesterase inhibitors such as aminophylline work?
Block the breakdown of cAMP and thus promote bronchodilation as cAMP accumulates
67
List the 4 second messengers working in the bronchial smooth muscle cell.
1. cAMP 2. cGMP 3. Ca 4. IP3
68
When clonidine is given to the patient, there is a decreased in MAC of____%.
15-50%
69
What higher center regulates the SNS?
Hypothalamus
70
List 3 drugs that block nicotinic receptors at the autonomic ganglia.
1. Trimethaphan 2. d-Tubocurarine 3. Metocurine * Blocks transmission of sympathetic impulses - hypotension
71
Why does tachyphylaxis result from ephedrine use?
Depletion of NE from sympathetic postganglionic nerve terminals
72
How does phentolamine produce tachycardia?
Tachycardia reflects release of NE from sympathetic post-ganglionic nerve terminals owing to alpha-2 blockade