Parasympathetic NS

Question 1

Types of ACh synapse and where they’re found

Answer 1

Nicotinic - skeletal muscle, most autonomic ganglia and spinal motor neurones in ventral horn
Muscarinic - glands, smooth muscle, parasympathetic effectors

Question 2

Muscarinic receptor locations/functions

Answer 2

Smooth muscle (eye, bronchi, GI tract, bladder) innervated and contraction
Blood vessels, not innervated, relaxation
Arterioles in genitals, innervated, relaxation
Glands (salivary, lacrimal, GI tract, bronchial), innervated, secretion
Heart, innervated, slows rate/conduction - no effect on ventricular conduction

Question 3

Muscarinic agonists use

Answer 3

Pilocarpine for glaucoma and dry mouth, no others really used
Bethanechol formerly for urinary retention and paralysed ileum but superseded by catheterisation and laxatives

Question 4

tropsium, tolteroldine, oxybutynin uses

Answer 4

Urinary incontinence (tropsium, tolteroldine, oxybutynin)

Question 5

Tropicamide use

Answer 5

Tropicamide for retinal examination

Question 6

Atropine use

Answer 6

Atropine for eye surgery/ACh-ase poisoning

Question 7

Ipratropium/tiotropium use

Answer 7

Ipratropium/tiotropium for smooth muscle spasm e.g. in asthma

Question 8

hyoscine=scopolamine use

Answer 8

Anaesthesia pre-med (fewer secretions and sedated)

Hyoscine for motion sickness

Question 9

Problems with muscarinic block in elderly

Answer 9

Many common drugs block muscarinic receptors so these can summate and cause SEs