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Flashcards in Autonomic synapses Deck (92)
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1

All somatic motor fibres release...

ACh on nAChr

2

All pre ganglionic fibres release ...

ACh on nAChr on post ganglionic fibre

3

Post ganglionic parasympathetic fibres release ...

ACh on muscarinic receptors

4

Post ganglionic sympathetic fibres release ...

Noradrenaline on adrenergic receptors

Noradrenaline & neuropeptides on adrenergic/associated receptors

ACh on muscarinic (sweat glands only)

5

What is the innervation of sweat glands?

Sympathetic via ACh on muscarinic receptors

6

What is the only location of sympathetic response with ACh/Muscarinic receptors?

Sweat glands

7

What is muscarine?

Agonist for muscarinic receptors, doesn't bind nAChrs

8

What is nicotine?

Agonist for nAChr, doesn't bind to muscarinic receptors

9

What are muscarinic antagonists?

Atropine, cyclopentolate, hyoscoine

10

What is inhaled muscarinic antagonist?

Ipratromium bromide

11

How is atropine taken?

Orally or as injection

12

What is mecamylamine?

Block nicotinic receptor at ganglia

13

What condition can we use atropine for?

Bradycardia: acts on M2 on SAN and AVN

14

How do we treat urinary incontinence?

Darifenacin: M3 blocker, block smooth detrusor muscle contractions

15

What is pirenzipine and what do we use it for?

M1 blocker

Decrease stomach secretions and increase motility, used to treat ulcers

16

What 2 drugs affect autonomic ganglia?

Hexamethonium
Suxamethonium

17

What is the action of hexamethonium?

Non-depolarising ganglionic blocker, a nicotinic (nAChR) receptor antagonist.

18

What is the action of suxamethonium?

Depolarising drug, generates an action potential, AChE cannot remove the drug so the membrane cannot repolarise. The maintained depolarisation means that the voltage gated sodium channels are inactivated.

19

Where do preganglionic parasympathetic axons mainly arise from?

Brain stem

20

Are pre-ganglionic neurones myelinated?

Yes

21

Are post-ganglionic neurones myelinated?

No

22

What are the relative lengths of the sympathetic pre/post ganglionic neurones?

Preganglionic nerves are short and the postganglionic nerves are long.

23

What are the relative lengths of the parasympathetic pre/post ganglionic neurones?

Long preganglionic neurones and short postganglionic neurones

24

Where are the parasympathetic ganglia positioned?

Close to target

25

Do postganglionic autonomic neurones have end plates?

No

26

How do autonomic neurones innervate smooth and cardiac muscle?

Synapse en passant - vesicle containing varicosities along the axon, release NT

27

What is a varicosity?

Bulbous vesicle filled enlargements of the neurone

28

True or false, catecholamines are always excitatory?

True

29

Where is adrenaline released from?

Adrenal glands (adrenal medulla) chromaffin cells

30

Describe different locations of Adr and NA release?

NA: main neurotransmitter released by post ganglionic symp fibres

Adr: main hormone released by adrenal medulla