Autonomic Nervous System Flashcards

(46 cards)

1
Q

Define the autonomic nervous system?

A

Involuntary nervous system

Visceral motor system

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2
Q

What is the purpose of the ANS?

A

Homeostasis

Allostasis

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3
Q

What sorts of actions can the ANS have?

A

Part of simple reflexes
Involve coordinated regulation of multiple sites
Associated with more complex behaviour

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4
Q

What are the features of the ANS?

A

Precise
Flexible
Integrativ

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5
Q

What are the targets of autonomic nerves?

A
Smooth and cardiac muscle
Epithelial transport of ions
Hormones and mucous secretions
Metabolism
Immune cells
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6
Q

What are the components of the ANS?

A

Sympathetic
Parasympathetic
Enteric

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7
Q

Where are the parts of the sympathetic and parasympathetic nervous systems?

A

CNS

PNS

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8
Q

Do the sympathetic and parasympathetic nervous systems require the CNS for function?

A

Yes

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9
Q

Where is the enteric nervous system?

A

In GIT

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10
Q

Does the enteric nervous system need the CNS to function?

A

No, can function independently

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11
Q

What neurons make up the enteric nervous system?

A

Sensory
Motor
Interneurons

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12
Q

Do the sympathetic and parasympathetic nervous systems influence the enteric nervous system?

A

Yes

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13
Q

How are the sympathetic and parasympathetic nervous systems defined?

A

By their anatomy - location of their preganglionic neurons

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14
Q

Where are the sympathetic preganglionic neurons?

A

In thoraco-lumbar region of spinal cord

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15
Q

Where are the parasympathetic preganglionic neurons?

A

In cranio-sacral region of spinal cord

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16
Q

Which areas of the spinal cord have no visceral fibres?

A

Cervical and lumbar enlargements

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17
Q

What nucleus in the spinal cord are sympathetic preganglionic cell bodies located?

A

Intermediolateral nucleus

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18
Q

What are the two types of sympathetic ganglia?

A
Paravertebral = sympathetic chain
Prevertebral = mesenteric ganglia
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19
Q

Other than the sympathetic ganglia, what else do preganglionic sympathetic neurons innervate?

A

Adrenal medulla

20
Q

What is the sympathoadrenal system?

A

Preganglionic sympathetic neurons and adrenal medulla

21
Q

Where are the preganglionic parasympathetic cell bodies located?

A

Brainstem nuclei

Sacral spinal cord

22
Q

What are the preganglionic parasympathetic nuclei of the brainstem?

A

Edinger-Westphal nucleus
Salivatory nuclei
Dorsal motor nucleus of vagus and nucleus ambiguus

23
Q

Where do neurons project to from the Edinger-Westphal nucleus, and what do they control?

A

To ciliary ganglion to control sphincter pupillae and ciliary muscle

24
Q

Where do neurons project to from salivatory nuclei, and what do they control?

A

To submandibular, sphenopalatine, and otic ganglia to control lacrimal, salivary, sublingual, nasal, and palatine glands

25
Where do neurons project to from the dorsal motor nucleus of vagus and nucleus ambiguus, and what do they control?
To microganglia near and on outer surface of thoracic and abdominal organs, controlling many functions
26
Where in the sacral spinal cord is the parasympathetic preganglionic nucleus?
Interomediolateral nucleus
27
Where are sacral postganglionic parasympathetic neurons?
In pelvic/inferior hypogastric plexus
28
Are the pelvic ganglia purely parasympathetic?
No, they contain many sympathetic neurons > mixed ganglia
29
What is the clinical significance of the long axons of the pelvic plexus?
Vulnerable to surgical injury
30
Are ANS neurons myelinated or unmyelinated?
Unmyelinated
31
Where are neurotransmitters stored in postganglionic fibres?
In swellings along axon = varicosities | Can be released from any of them
32
What is the significance of transmitter release from varicosities?
Transmitter released over large area so it has large effect in coordinated way
33
What is the preganglionic transmitter, and what receptor does it act on?
ACh | Nicotinic receptors
34
What is the postganglionic sympathetic neurotransmitter and what receptor does it act on?
NA (most) Alpha/beta adrenoceptors ACh (few) Muscarinic receptors
35
What is the postganglionic parasympathetic neurotransmitter, and what receptor does it act on
ACh | Muscarinic receptors
36
How many subtypes of ACh and NA receptors are there?
Many
37
Are ACh and NA the only transmitters used by the ANS?
No, many others used
38
How does the ANS gather information?
Caudal part of nucleus of thee solitary tract (NTS) in medulla receives sensory input
39
What is the major integrative centre of autonomic function?
NTS
40
Where is sensory information distributed to?
Provide feedback to reflexes > control organ/tissue function | Provide info to higher centres to drive more complex responses
41
What is the role of the hypothalamus in the ANS?
Receives - Sensory inputs - Contextual info from other brain regions - Hormonal signals Compares situation to biological set points > adjusts behaviour, autonomic and endocrine function
42
What does the fight or flight response involve?
Mass activation of many sympathetic pathways at once to overcome/escape from major threat
43
Why doe mass activation and synchronisation occur in the fight or flight response?
CNS activates many preganglionic pathways at once Some preganglionic neurons have many axon collaterals > activate many postganglionic neurons at once When adrenal medulla activated catecholamine hormones spread through bloodstream
44
When is mass activation of the sympathetic nervous system relevant?
Extreme situation
45
How does the sympathetic nervous system mediate functions essential for normal living?
Individual cells/tissues/organs precisely and independently activated Adrenal medulla nerves not always activated
46
Why is there limited mass activation of different types of parasympathetic pathways?
No equivalent of adrenal gland Preganglionic neurons don't have as many axon collaterals to simultaneously activate numerous postganglionic neurons Most coordination of pathways between different regions occurs by brain mechanisms