Let 4- ANS

Question 1

revision

Answer 1

• Pre-ganglionic neurons: acetylcholine acting on nicotinic cholinergic receptors
• Post-ganglionic sympathetic neurons: Noradrenaline (norepinephrine) acting on alpha or beta-adrenoceptors
• Post-ganglionic parasympathetic neurons: acetylcholine acting on muscarinic cholinergic receptors

Question 2

Revision

Answer 2

• SYMPATHETIC: contraction of vascular smooth muscle; urinary retention; Dilation of the pupils; sweating
• PARASYMPATHETIC: Bradycardia; Bronchoconstriction; increased GI motility; insulin secretion from the pancreas

Question 3

The autonomic nervous system

Answer 3

• Antagonist Control: branches of ANS have opposing effects on target tissue
• Tonic Control: variable response depending on level of input
• Variable tissue responses: different receptor populations

Question 4

the release of neurotransmitter

Answer 4

• Action potential arrives at the varicosity
• Depolarisation open voltage-gated Ca2+ channels
• Ca2+ entry triggers exocytosis of synaptic vesicles
• NE binds to adrenergic receptors on targets
• Activity ceases when NE diffuses away from the synapse
• NE is transported back into the axon
• NE can be taken back into synaptic vesicles for re-release
• NE is metabolized by monoamine oxidases (MAO)

Question 5

Neurotransmitters 1-7

Answer 5

1) uptake of precursor
2) synthesis of the transmitter
3) storage in vesicles
4) degradation of surplus
5) depolarization
6) influx of Ca2+
7) exocytosis

Question 6

Neurotransmitter 8-13

Answer 6

8) Diffusion to postsynaptic membrane
9) interaction with receptors
10) inactivation
11) reuptake of transmitter or degradation product by nerve terminal
12) Uptake by non-neuronal cells
13) interactions with pre-synaptic receptors

Question 7

Drugs which modulate the ANS

Answer 7

• High BP
• Cardiac arrhythmias
• Asthma
• Incontinence
• Glaucoma
• Depression