Autonomic Nervous System Flashcards Preview

MD1 Neuroscience > Autonomic Nervous System > Flashcards

Flashcards in Autonomic Nervous System Deck (46):
1

Define the autonomic nervous system?

Involuntary nervous system
Visceral motor system

2

What is the purpose of the ANS?

Homeostasis
Allostasis

3

What sorts of actions can the ANS have?

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

4

What are the features of the ANS?

Precise
Flexible
Integrativ

5

What are the targets of autonomic nerves?

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

6

What are the components of the ANS?

Sympathetic
Parasympathetic
Enteric

7

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

CNS
PNS

8

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

Yes

9

Where is the enteric nervous system?

In GIT

10

Does the enteric nervous system need the CNS to function?

No, can function independently

11

What neurons make up the enteric nervous system?

Sensory
Motor
Interneurons

12

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

Yes

13

How are the sympathetic and parasympathetic nervous systems defined?

By their anatomy - location of their preganglionic neurons

14

Where are the sympathetic preganglionic neurons?

In thoraco-lumbar region of spinal cord

15

Where are the parasympathetic preganglionic neurons?

In cranio-sacral region of spinal cord

16

Which areas of the spinal cord have no visceral fibres?

Cervical and lumbar enlargements

17

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

Intermediolateral nucleus

18

What are the two types of sympathetic ganglia?

Paravertebral = sympathetic chain
Prevertebral = mesenteric ganglia

19

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

Adrenal medulla

20

What is the sympathoadrenal system?

Preganglionic sympathetic neurons and adrenal medulla

21

Where are the preganglionic parasympathetic cell bodies located?

Brainstem nuclei
Sacral spinal cord

22

What are the preganglionic parasympathetic nuclei of the brainstem?

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

23

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

To ciliary ganglion to control sphincter pupillae and ciliary muscle

24

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

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

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