Synapses

Question 1

define synaptic cleft

Answer 1

The small gap between 2 neurones

Question 2

define cholinergic synapse

Answer 2

use acetylcholine as a neurotransmitter

Question 3

define pre-synaptic knob

Answer 3

swelling at the end of the presynaptic neurone

Question 4

describe the stages of transmission

Answer 4

1) action potential arrives at the pre-synaptic neurone
2) calcium channels in the membrane open and ions flood in
3) synaptic vesicles move towards the pre synaptic membrane
4) vesicles fuse w/ membrane, releasing acetylcholine via exocytosis
5) acetylcholine binds w/ receptor on the postsynaptic membrane
6) sodium channels on the postsynaptic membrane open
7) Na+ move into the cell, causing depolarisation on the postsynaptic neurone
8) an action potential is generated in the postsynaptic cleft

Question 5

define acetylcholinesterase

Answer 5

an enzyme that hydrolyses acetylcholine into acetic acid and choline in the synaptic cleft

Question 6

Name reasons for hydrolysis

Answer 6

1. stops continuous production of a.p in postsynaptic neurone
2. recycles the acetylcholine

Question 7

What happens once the acetylcholine is hydrolysed?

Answer 7

acetic acid _ choline diffuse back into the pre-synaptic knob

then combined back into acetylcholine using energy

then stored in the vesicles