ANS Flashcards

1
Q

What are the functions of the ANS?

A

Maintain homeostasis
Respond to changing physiologic conditions
Increase or decrease effector activity

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2
Q

What are the 2 division of the ANS?

A

Sympathetic NS

Parasympathetic

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3
Q

Where on the spinal cord does the SNS originate?

A

Thoraco-lumbar

T1-L2

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4
Q

Where on the spinal cord does the PSNS originate from?

A

Cranio-sacral

Cranial nerves and S2-S4

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5
Q

What cranial nerves have PSNS fibers?

A

III
VII
IX
X

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6
Q

Where are the sympathetic ganglia?

A

Near the spinal cord

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7
Q

Where are the parasympathetic ganglia?

A

Near the target organ

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8
Q

Describe preganglionic efferent fibers:
+/- myelin
Fiber type
Short or long

A

Preganglionic efferent SNS fibers are
Myelinated
Type B
Short

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9
Q

Describe preganglionic efferent PSNS fibers:
+/- myelin
Fiber type
Short or long

A

Preganglionic efferent PSNS fibers are:
Myelinated
Type B
Long

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10
Q

Describe postganglionic efferent SNS fibers:
+/- myelin
Fiber type
Short or long

A

Postganglionic efferent SNS fibers are:
Unmyelinated
Type C
Long

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11
Q

Describe postganglionic efferent PSNS fibers:
+/- myelin
Fiber type
Short or long

A

Postganglionic efferent PSNS fibers are:
Unmyelinated
Type C
Short

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12
Q

What is the sympathetic chain, and what is another name for it?

A

The sympathetic chain is a bundle of nerves that runs from the base of the skull to the coccyx just lateral to the vertebral bodies
Paravertebral ganglia

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13
Q

What supplies the sympathetic chain?

A

Rami communicates

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14
Q

What are the 2 branches of the rami communicates?

A
White ramus (myelinated)
Grey ramus (unmyelinated)
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15
Q

Where is the preganglioic cell body in the SNS?

A

The lateral horn of the spinal cord

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16
Q

What spinal root do the SNS fibers pass through?

A

The ventral root and into the corresponding spinal nerve

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17
Q

What is the first ramus SNS fibers pass through after leading the spinal canal, and where to the continue to?

A

The White ramus and into the sympathetic chain

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18
Q

What are the 3 paths a preganglionic SNS fiber can take after reaching the sympathetic chain?

A
  1. Synapse at the same level
  2. Travel up or down the chain to synapse
  3. Exit to synapse at a ganglion outside the sympathetic chain
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19
Q

What is the place where SNS preganglioic fibers travel to synapse if they just pass through the sympathetic chain?

A

Prevertebral ganglion
AKA
Contralateral ganglia

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20
Q

If the SNS synapse occurs in the sympathetic chain what are the 2 things that can happen next with the postganglionic fiber?

A
  1. Travel to the target organ
  2. Enter the grey ramus leading back to the spinal nerve and follow the skeletal nerve to blood vessels of skeletal muscle, piloerector muscle, or sweat glands
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21
Q

What is the most significant prevertebral ganglia to anesthesia?

A

Stellate ganglion

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22
Q

What is the stellate ganglion? How does blockage manifest?

A

Provides sympathetic inner action to the IPSP lateral upper extremity and a portion of the head and neck.
Blockade manifests as Horner’s syndrome: ptosis, anhydrous is, miosis, and enophthalmos

23
Q

What activity is the majority of PSNS activity?

A

Vagus

75% (3/4)

24
Q

Responses in which ANS division are energy conserving and which are energy expending?

A

Responses in the SNS are generally energy expending

Responses in the PSNS are generally energy conserving

25
Do all organs have SNS and PSNS innervation?
No, some have both and some only have one
26
Give an example of something that is only innervated by one ANS division
Blood vessels are only innervated by the SNS. SNS causes vasoconstriction Vasodilation is caused by just less SNS activity
27
What is the neurotransmitter utilized by preganglionic fibers in the SNS? PSNS?
All preganglionic fibers are cholinergic and use acetylcholine
28
What neurotransmitter is utilized by postganglionic fibers in the SNS? PSNS
SNS: are adrenergic and use norepinephrine (expect for sweat glands) PSNS: are cholinergic and use acetylcholine
29
What neurotransmitter do cholinergic synapses respond to?
Acetylcholine
30
Where are cholinergic synapses located (3)?
ANS ganglia PNS end organ Neuromuscular junction
31
What are the receptors types at cholinergic synapses?
Nicotinic | Muscarinic
32
What are the subtypes of Nicotinic cholinergic receptors? Where are each located?
Nn: SNS ganglionic synapse and PSNS ganglionic synapse Nm: Neuromuscular junction
33
Where are muscarinic receptors located?
At the PSNS end organs | Also found at SNS end organ sweat glands
34
What muscarinic receptor subtype is specifically important to Taylor and why?
M2: stimulation by PSNS at M2 causes bradycardia
35
What do adrenergic synapses respond to?
Endogenous catecholamines: Norepinephrine Epinephrine Dopamine
36
What are the 2 types of adrenergic receptors?
Alpha | Beta
37
What adrenergic receptor(s) does norepinephrine stimulate?
Alpha
38
What adrenergic receptor(s) does epinephrine stimulate?
Both alpha and beta
39
Where are most alpha 1 receptors located? What stimulates them? What is the response?
Most are located in vascular smooth muscle Stimulated by norepinephrine Causes vasoconstriction (Phenylephrine, levophed)
40
What happens if alpha 1 antagonists are given?
Vasodilation | Prazosin
41
Where are beta 1 receptors mostly located? What stimulates them? What is the response?
Most beta 1 receptors are located in the heart. Stimulated by epinephrine and norepinephrine. Response is increased HR, contractility, automaticity and conduction (Dobutamine, dopamine, isoproterenol-mixed)
42
What happens if beta 1 antagonists are given?
Cardiac depression | Metoprolol etc., propranolol-mixed
43
Where are beta 2 receptors located? What stimulates them? What is the response?
Beta 2 receptors are located in some blood vessels (skeletal and coronaries), bronchioles, uterus, kidney, liver, pancreas. Stimulated by epinephrine and norepinephrine. Responses: vasodilation, bronchodilation, smooth muscle relaxation, improved glucose metabolism
44
Where are dopamine receptors located? What stimulates them? What is the response?
In the kidneys and splanchnic vasculature. Stimulated by dopamine. Response: relaxation, increased blood flow to kidneys and abdominal viscera
45
If the dopamine receptor is not considered adrenergic, why is dopamine considered an adrenergic agonist?
Because at higher doses dopamine does agonize other adrenergic receptors
46
Where are alpha 2 receptors located? What stimulates them? What is the response?
Found presynaptically and in the CNS. Stimulated by norepinephrine. Engaged alpha 2 receptor acts to inhibit neurotransmitter release by that neuron resulting in decreased SNS activity
47
Most blood vessels are pure have what receptor?
Alpha 1 - stimulation causes vasoconstriction and less stimulation causes dilation
48
Skeletal muscle vessels have what receptor?
Beta 2 - stimulation causes vasodilation
49
Besides beta 2, what other receptor do skeletal muscle vessels also have?
Sympathetic cholinergic (muscarinic) - stimulation causes vasodilation
50
What is dysautonomia?
ANS dysfunction
51
What s/sx are seen with ANS dysfunction?
``` Orthostatic hypotension - baroreceptor would be impaired Urinary retention Bowel dysfunction Impotence Parkinsonism - Parkinson-like symptoms ```
52
What can cause ANS dysfunction?
Degeneration - Shy Drager Neuropathy - like from DM Inherited Idiopathic
53
What are the anesthesia implication of ANS dysfunction?
Hypotension - to with volume, direct acting pressors