Autonomic Function and Dysfunction

Question 1

Is there a difference between neuronal and muscle nicotinic receptors?

Answer 1

Both bind ACh but produce different response

Question 2

‘He is pink complexioned’

Answer 2

his vascular tone has changed, skin only innervated by sympathetic so dilation

Question 3

‘When he is stood in a queue he become pale and faint’

Answer 3

body wide vasodilation, blood accumulates in feet/legs

Question 4

‘He is longsighted’

Answer 4

ciliary muscles of lens innervated by parasymp only

Question 5

‘He is easily blinded by bright light’

Answer 5

Iris is innervated by symp and parasymp but parasymp is dominant, pupils dilate

Question 6

Predict the effect on his heart rate at rest

Answer 6

At rest parasymp dominates, if autonomic control lost, his heart rate will increase

Question 7

Why does hexamethonium affect the GI tract?

Answer 7

Because it is innervated by SNS, PNS and ENS

Question 8

What affect does hexamethonium have on secretion?

Answer 8

reduced saliva
no tears
no peptic ulcer
no sweat
constipation

Question 9

Where does hexamethonium act? How does it produce its effect?

Answer 9

its a nicotinic ACh recpetor antagonist that acts in symp and parasymp ganglia