5.1.3 Cholinergic synapses

Question 1

Give an example of an inhibitory neurotransmitter.

Answer 1

• GABA.

Question 2

What happens to the postsynaptic neurone if it receives a inhibitory neurotransmitter?

Answer 2

• Does not trigger a new action potential.

Question 3

Give an example of an excitatory neurotransmitter.

Answer 3

• Acetylcholine.

Question 4

What happens to the postsynaptic neurone if it receives a excitatory neurotransmitter?

Answer 4

• Triggers new action potential.

Question 5

When the action potential arrives at the presynaptic neurone, what does this cause?

Answer 5

• The voltage-gated calcium channels to open.

Question 6

What do the calcium ions trigger when they enter the presynaptic neurone?

Answer 6

• The vesicle containing acetylcholine to fuse with the cell surface membrane releasing acetylcholine via exocytosis.

Question 7

What happens to acetylcholine after it has left the presynaptic neurone?

Answer 7

• Crosses the synaptic cleft, binding to the receptor sites on the postsynaptic neurone, opening the postsynaptic sodium ion channels, allowing sodium to enter the postsynaptic neurone.

Question 8

What happens after sodium ions have entered the postsynaptic neurone?

Answer 8

• Once sodium ions have entered the postsynaptic neurone, the sodium ions travel down the electrochemical gradient causing depolarisation of the postsynaptic neurone triggering a new action potential.

Question 9

What is the enzyme that breaks down acetylcholine?

Answer 9

• Acetylcholinesterase.

Question 10

What are the products from the acetylcholinesterase breaking down acetylcholine?

Answer 10

• Acetate and choline.

Question 11

What molecule helps acetate and choline form acetylcholine?

Answer 11

• ATP.