Lecture 1 Qs - Questions on Introduction to ANS

Question 1

What effect would blockade of nicotinic acetylcholine receptors have on heart rate at rest and during exercise?

Answer 1

Parasympathetic dominates at rest = heart rate increases

Sympathetic dominates during exercise = heart rate decreases

Question 2

Would bronchoconstriction occur after blockade of nicotinic acetylcholine receptors at rest?

Answer 2

No, at rest parasympathetic dominates so lungs tend to be bronchoconstricted anyway, sympathetic causes dilation

Question 3

Would sweat production be increased after blockade of nicotinic ACh receptors at rest?

Answer 3

No, parasympathetic fibres not involved in sweat production, only sympathetic

Question 4

Would constipation occur if nicotinic ACh receptors were blocked?

Answer 4

Yes, parasympathetic dominates at rest, promotes gut motility, reduced gut motility after blockade results in constipation

Question 5

How would urinary frequency change if nicotinic ACh receptors were blocked?

Answer 5

Frequency would decrease as parasympathetic fibres stimulate detrusor contraction and sphincter relaxation

Question 6

How would eye sight change if nicotinic ACh receptors were blocked?

Answer 6

Long-sightedness would occur as parasympathetic allows for short-sightedness so blockade disables this

Question 7

Blockade of which of the following receptor sub-types would induce both INCREASED heart rate and REDUCED sweat production during exercise?

• Muscarinic
• a1 adrenoceptors
• a2 adrenoceptors
• b1 adrenoceptors
• b2 adrenoceptors

Answer 7

Muscarinic receptors
These are found on parasympathetic innervated organs so in this case on the heart. When blocked, parasympathetic stimulation of the heart is blocked and so heart rate rises.
These are also found on sweat glands as sympathetic stimulated receptors so when blocked there is less sweat produced.

Question 8

Blockade of which of the following targets would cause the most significant rise in synaptic noradrenaline concentrations?

• Tyrosine hydroxylase
• DOPA decarboxylase
• Uptake 1 transport protein
• Monoamine oxidase
• Cathecol-O-methyl Transferase

Answer 8

Uptake 1 transport protein.
This protein moves Noradrenaline from the synapse back into the pre-synaptic neurone for metabolism or recycling. Blocking this protein causes the greatest increase in synaptic concentration of noradrenaline as its reuptake is now blocked.