Synaptic transmission

Question 1

What is a neurotransmitter?

Answer 1

Neurotransmitters are chemicals that diffuse across the synapse to the next neuron in the chain.

Question 2

Outline the structures and processes involved in synaptic transmission.

Answer 2

1. An impulses arrives at end of the presynaptic neurone.
2. Vesicles move towards, and fuse with the presynaptic membrane and this releases neurotransmitters into the synaptic cleft.
3. The neurotransmitters diffuse across the synaptic cleft down a concentration gradient.
4. Neurotransmitters attach to the receptors on the postsynaptic membrane.
5. This triggers and impulse which travels along the postsynaptic neurone.
6. The neurotransmitters are recycled or destroyed once an impulse is sent.

Question 3

What is an excitatory neurotransmitter?

Answer 3

Excitatory neurotransmitters make a neuron more positively charged. The more positively charged a neuron, the more likely it is to fire.

Question 4

Give an example of an inhibitory neurotransmitter.

Answer 4

Serotonin

Question 5

Give an example of an excitatory neurotransmitter.

Answer 5

Adrenaline.

Question 6

What is summation?

Answer 6

The question of wether a postsynaptic neuron will fire. The excitatory and inhibitory influence are summed, if the net effect on the post synpatic neuron is inhibitory (negative) then the neuron is less likely to fire.

Question 7

Why can neurotransmitters not travel back through the synapse?

Answer 7

There are no receptors on the presynpatic neuron. Diffusion must go from a high concentration to a low concentration.

Question 8

What is the area inbetween the pre-synaptic neuron and post-synaptic neuron called?

Answer 8

The synaptic cleft.