Synaptic Transmission (Neurotransmitter Release)

Question 1

What is the first step in synaptic transmission?

Answer 1

Neurotransmitter (NT) is synthesized and stored in synaptic vesicles.

Question 2

What triggers the release of neurotransmitters from the presynaptic neuron?

Answer 2

Action potential arrives at the presynaptic terminal, opening voltage-dependent calcium channels.

Question 3

What happens when calcium ions enter the presynaptic terminal?

Answer 3

Calcium ions trigger the release of neurotransmitters from synaptic vesicles into the synaptic cleft.

Question 4

How do neurotransmitters affect the postsynaptic neuron?

Answer 4

Neurotransmitters bind to receptors on the postsynaptic neuron, leading to either EPSP (Excitatory) or IPSP (Inhibitory).

Question 5

What does an EPSP cause in the postsynaptic neuron?

Answer 5

EPSP: Depolarizes the neuron, making it more likely to fire.

Question 6

What does an IPSP cause in the postsynaptic neuron?

Answer 6

IPSP: Hyperpolarizes the neuron, making it less likely to fire.

Question 7

How is the action of neurotransmitters terminated?

Answer 7

Neurotransmitters are removed from the synaptic cleft by reuptake or enzymatic breakdown.