L3 - Synaptic Transmission

Question 1

Pre-synaptic Neuron

Answer 1

The neuron transferring the action potential

Question 2

Post-synaptic neuron

Answer 2

The neuron receiving the action potential

Question 3

Action potential

Answer 3

Neurons transmit electrical impulses = action potential

Between pre-synaptic neuron and post-synaptic neuron

Question 4

Exocytosis

Answer 4

Exocytosis occurs:
- when the action potential reaches the pre-synaptic terminal, it triggers the release of neurotransmitters from vesicles

Question 5

Vesicles

Answer 5

Sacs on the pre-synaptic membrane that release neurotransmitters

Question 6

Synaptic cleft

Answer 6

Physical gap between the pre-synaptic membrane + post-synaptic membrane

Question 7

What happens after exocytosis?

Answer 7

• the released neurotransmitter will diffuse across the synaptic cleft
• where it binds to specialised post-synaptic receptor sites

Question 8

Re-uptake

Answer 8

• synaptic transmission takes only a fraction of a second + effects terminated by process called re-uptake
• neurotransmitter is taken back by the vesicles so stored for later release
• the quicker the neurotransmitter is taken back, the shorter the effects

Question 9

What can neurotransmitters be?

Answer 9

• excitatory

- inhibitory

Question 10

Excitatory neurotransmitters

Answer 10

• excitatory neurotransmitters cause an electrical charge in the membrane of the post-synaptic neuron
• resulting in an EPSP
• means that post-synaptic neuron is more likely to fire an impulse

Question 11

EPSP

Answer 11

Excitatory post-synaptic potential

Question 12

Inhibitory neurotransmitters

Answer 12

• cause IPSP

- making it less likely that the neuron will fire an impulse

Question 13

IPSP

Answer 13

Inhibitory post-synaptic potential

Question 14

Can a neurons receive both EPSPs and IPSPs at the same time?

Answer 14

A Neurons can receive both EPSPs + IPSPs at the same time

Question 15

What is the likelihood that the neurons will fire an impulse?

Answer 15

• likelihood that the neuron will fire an impulse is determined by adding up the excitatory + inhibitory synaptic input
• summation then determines whether or not the neuron will fire an impulse
• if net effect is inhibitory = neuron won’t fire
• if net effect is excitatory = neuron will fire

Question 16

Summation

Answer 16

• the net result of adding up the excitatory + inhibitory synaptic input