Lesson 3 - The process of synaptic transmission

Question 1

What is synaptic transmission?

Answer 1

• The process by which nerve impulses are transmitted across the synaptic cleft between one neuron (pre-synaptic) and the next neuron (post-synaptic).
• The nerve impulse is carried by chemicals called neurotramitters

Question 2

What is the synapse?

Answer 2

The neuron/nerve ending (found at the end of the axon)

Question 3

Difference between electrical impulses and neurotransmitters

Answer 3

• Within an individual neuron, messages are transmitted by electrical impulses
• Between one neuron and the next, messages are transmitted by neurotransmitters

Question 4

Where are neurotransmitters

located?

Answer 4

In vesicles in the pre-synaptic neuron

Question 5

The release of neurotransmitters:

Answer 5

When electrical impulses travel along the axon, it prompts the release of neurotransmitters at the pre-synaptic knob

Question 6

What is the synaptic knob?

Answer 6

A swelling in the pre synaptic neuron which contains synaptic vesicles filled with neurotransmitters

Question 7

What are synaptic vesicles?

Answer 7

Tiny sacs in the synaptic knob of the pre-synaptic neuron

Question 8

Neutrotrasnmitters are released into the synaptic fluid in the synaptic cleft…

Answer 8

…and this results in an action potential

Question 9

What is ‘action potential’

Answer 9

Neurons send information along the axon away from the cell body which creates an action potential

Question 10

The 2 types of action potential:

Answer 10

Excitation (next neuron continues to fire and be activated)

Inhibition (next neuron does not fire)

Question 11

Excitatory potential

Answer 11

1. A neurotransmitter is released from the synaptic vesicles (from the pre synaptic neuron) into the synaptic cleft.
2. The neurotransmitter is likely to bind with the post synaptic receptor cells and cause a positive electrical charge in the membrane of the post synaptic neuron.
3. The post synaptic neuron will be positively charged and is likely to fire. It will continue to pass on the chemical impulse (from the synapse) as an electrical impulse (in the post synaptic neuron)
4. The process then continues to the next neuron

Question 12

Excitatory potential example:

Answer 12

Adrenaline - a hormone and a neurotransmitter and is responsible for the fight/flight response.
This causes a positive charge to be built up in the post synaptic neuron.

Question 13

Inhibitory potential:

Answer 13

1. A neurotransmitter is released from the synaptic vesicles (from the pre synaptic neuron) into the synaptic cleft.
2. The neurotransmitter is less likely to bind with the post synaptic receptor cells and will cause a negative electrical charge in the membrane of the post synaptic neuron.
3. The post synaptic neuron will be negatively charged and is not likely to fire. It will not continue to pass on the chemical impulse (from the synapse)

Question 14

Inhibitory potential example:

Answer 14

Serotonin (linked with emotion and mood e.g. low levels of serotonin leads to depression) - Serotonin causes inhibition in the post synaptic neuron meaning that it is unlikely to fire and be activated.
A negative charge is built up in the post synaptic neuron.