Synapses

Question 1

What is a synapse?

Answer 1

A synapse is a junction that transfers an electrical impulse between two neurones, or a neurone and a muscle fibre.

Question 2

What are the 4 components of a synapse?

Answer 2

• Presynaptic neurone
• Synaptic knob
• Synaptic cleft
• Postsynaptic neurone

Question 3

Within the presynaptic neurone, how are neurotransmitter molecules trnasported?

Answer 3

Synaptic vesicles

Question 4

What do presynaptic neurones also contain a lot of?

Answer 4

Mitochondria

Question 5

On which membrane (post or presynaptic) are the voltage-gated sodium and calcium channels on?

Answer 5

Presynaptic neurone

Question 6

On which membrane (post or presynaptic) are the sodium channels with receptor sites complementary to the neurotransmitter?

Answer 6

Postsynaptic neurones

Question 7

Synapses are unidirectional. What does this mean?

Answer 7

Synapses can only pass information in one direction across a synapse, from the presynaptic neurone to the postsynaptic neurone.

Question 8

Describe spatial summation.

Answer 8

Multiple different presynaptic neurones release enough neurotransmitters at once to exceed the threshold potential and trigger an action potential.

Question 9

Describe temporal summation.

Answer 9

A single presynaptic neurone releases neurotransmitters many times over a very short period to exceed the threshold potential and trigger an action potential.