Transmission Across A Synapse

Question 0

In what two ways can drugs act on synapses?

Answer 0

They can stimulate the nervous system by creating more action potentials in post synaptic neurones or inhibit the nervous system by creating fewer action potentials

Question 1

In what type of synapse is the neurotransmitter a chemical called acetylcholine?

Answer 1

A cholinergic synapse

Question 2

What does the arrival of an action potential at the end of the presynaptic neurone cause?

Answer 2

Calcium ion channels to open and calcium ions to enter the synaptic knob

Question 3

What does the influx of calcium ions into the presynaptic neurone cause?

Answer 3

The synaptic vesicles to fuse with the presynaptic membrane, so releasing acetylcholine into the synaptic cleft

Question 4

What do the acetylcholine molecules fuse with once released from the vesicles, and what does this cause?

Answer 4

Receptor sites on the sodium ion channel in the membrane of the post synaptic neurone which causes them to open and allow sodium ions to diffuse in rapidly along a concentration gradient

Question 5

What does the influx of sodium ions generate?

Answer 5

A new action potential in the post synaptic neurone

Question 6

What does the acetylcholinesterase do?

Answer 6

It hydrolyses acetylcholine into choline and ethanoic acid which diffuse back across the synaptic cleft and into the presynaptic neurone to be recycled

Question 7

What does the breakdown of acetylcholine prevent?

Answer 7

It prevents it from continuously generating a new action potential in the post synaptic neurone

Question 8

How is the choline and ethanoic acid recombined in the presynaptic neurone?

Answer 8

By ATP released from mitichodria