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Flashcards in The Autonomic Nervous System Deck (37):
1

What are the 5 regions of the brain stem/spinal cord, starting superiorly?

Medullary
Cranial
Thoracic
Lumbar
Sacral

2

Which region of the spinal cord do sympathetic nerve fibres stem from?

Thoracic region
Lumbar region

3

What part of the spinal cord do parasympathetic nerve fibres stem from?

Medullary
Sacral

4

Where is the vagus nerve found? What does it control?

In the medullary region

Controls heart rate

5

Where are parasympathetic ganglia located?

In the innervated tissues

6

Where are sympathetic ganglia located?

In the paravertebral chain, near the spinal cord

7

What are the structures of the preganglionic and postganglionic parasympathetic nerve fibres?

Preganglionic = long myelinated
Postganglionic = short unmyelinated

8

What are the structures of the preganglionic and postganglionic nerve fibres in the sympathetic nervous system?

Preganglionic = short myelinated
Postganglionic = long unmyelinated

9

What are the primary neurotransmitters of the ANS?

ACh
NA

10

All preganglionic neurones in the ANS use which neurotransmitter?

ACh (cholinergic)

11

What receptors does ACh work on at preganglionic neurone synapses?

Nicotinic ACh receptors

12

What types of receptors are nicotinic ACh receptors?

Ligand gated ion channels

13

What neurotransmitter and receptors are found at postganglionic parasympathetic neurones?

Acetylcholine

Muscarinic ACh receptors

14

What are the subtypes of muscarinic ACh receptors? What type of receptor is it?

m1 to m5

GPCR

15

What neurotransmitter and receptors are found at postganglionic sympathetic neurones?

Noradrenaline

Adrenoceptors

16

What subtypes of adrenoceptors exist? What type of receptor is it?

A1,a2, b1, b2, b3

GPCRs

17

Are all sympathetic postganglionic neurones adrenergic?

No some are cholinergic

E.g. Those innervating sweat glands, hair follicles

18

What other neurotransmitters are found in the ANS?

NANC transmitters such as NO and ATP are found in the ANS
Usually correlated with ACh or NA

19

What do chromaffin cells release?

Adrenaline

20

What results in the release of neurotransmitter at synapses?

Depolarisation dependent influx of calcium ions

21

How is ACh synthesised? Which enzyme catalyses the reaction?

Acetyl coA + choline ----> Acetycholine + coenzyme A

Choline acetyltransferase

22

How is acetylcholine degraded? Which enzyme catalyses this reaction?

Acetylcholine ----> choline + acetate

Acetylcholinesterase

23

What is trimethaphan used for?

Used in hypertensive emergencies and in surgery to block nAChRs

24

What is tolterodine?

A m3 antagonist --> used to treat an overactive bladder

25

Give an example of an acetylcholinesterase inhibitor?

Donepezil to treat Alzheimer's disease

26

What is SLUDGE a mnemonic for?

The effects of massive discharge of the parasympathetic nervous system - chronic over stimulation of mAChRs

27

What does SLUDGE stand for?

Salivation
Lacrimation
Urination
Defecation
GI upset
Emesis

28

What is lacrimation and emesis?

Tearing

Vomiting

29

When is SLUDGE encountered?

When there has been;

Drug overdose
Magic mushroom ingestion
Nerve gases
Exposure to insecticides

30

What is the treatment for SLUDGE?

Atropine
Pralidoxime

Both anti-cholinergic agents

31

Give an example of mAChR agonists and what they are used to treat?

Pilocarpine - treat glaucoma

Bethanecol - stimulate bladder emptying

32

Give an example of mAChR antagonists and what they are used to treat?

Ipratropium - asthma and COPD

Tolterodine - overactive bladder

33

What is the structure of post ganglionic sympathetic neurones?

They are highly branched and consist of bulges called varicosities where NA can be released

34

How is NA synthesised? Which enzymes are used?

Tyrosine --> DOPA ---> Dopamine---> NA

1) tyrosine hydroxylase
2) dopa decarboxylase
3) dopamine b-hydroxylase

35

What happens following calcium-dependent release of NA?

NA diffuses across the synaptic cleft

Binds with postsynaptic adrenoceptors initiating the signal
Binds with presynaptic adrenoceptors regulating NA release

36

How is NA degraded in the synaptic cleft?

Removed by NA transporter proteins

1) removed by high affinity Na+ dependent transporter
2) remaining NA removed by low affinity neuronal mechanism

37

In the presynaptic terminal, NA not packaged into vesicles is removed by... (2)

Monoamine oxidase
Catechol-O-methyltransferase