Synapses

Question 1

what is a synpase?

Answer 1

• the junction between two neurones OR a neurone and effector

Question 2

what are the key structures of a synapse:

Answer 2

• synaptic cleft
• presynpatic neurone
• postsynaptic neurone
• synaptic knob
• synaptic vesicles
• neurotransmitter receptors?

Question 3

what is a synaptic cleft?

Answer 3

• the gap which separates the axon of one neurone from the dendrite of the next neurone

Question 4

what is a presynaptic neurone?

Answer 4

• neurone along which the impulse has arrived

Question 5

what is a postsynaptic neurone?

Answer 5

• neurone that receives the neurotransmitter

Question 6

what is the synaptic knob?

Answer 6

• the swollen end of the presynaptic neurone
• contains many mitochondria and ER to enable it to manufacture neurotransmitters

Question 7

what are synaptic vesicles?

Answer 7

• vesicles that contain neurotransmitters
• fuse with the presynaptic membrane and release their contents into the synaptic cleft

Question 8

what are neurotransmitter receptors?

Answer 8

• receptor molecules which the neurotransmitter binds to in the post synpatic membrane

Question 9

what are the two groups of neurotransmitters?

Answer 9

• excitatory
• inhibitory

Question 10

what is an excitatory neurone?

Answer 10

• result in depolarisation of the post synaptic neurone
• action potential triggered if threshold is met
• e.g acetylcholine

Question 11

what is an inhibitory neurotransmitter?

Answer 11

• result in hyperpolarisation of the postsynaptic membrane
• prevents action potential being triggered
• e.g. GABA