Synaptic Transfer And Neurotransmitters

Question 1

What are synapses?

Answer 1

The physical gaps that separate neurons from other neurons and receptor or effector cells

Question 2

How do neurons transmit information?

Answer 2

Convert electrical signal into chemical signal

Question 3

What is the first step of the chemical transfer across synapses?

Answer 3

A neurotransmitter is synthesised and stored in vesicles of the presynaptic neuron.

Question 4

What happens after a neurotransmitter is made and stored in vesicles of the presynaptic neuron?

Answer 4

Action potential reaches the presynaptic terminal.

Question 5

What happens after an action potential reaches the presynaptic terminal?

Answer 5

The presynaptic terminal depolarizes which results in the voltage gated calcium channels to open

Question 6

What happens when the voltage gated calcium channels opens?

Answer 6

There is an influx of calcium through channels

Question 7

What happens when calcium flows through the voltage gated calcium channels?

Answer 7

The vesicles containing the neurotransmitter fuse with a presynaptic membrane.

Question 8

What happens when the vesicles fuse with a presynaptic membrane?

Answer 8

The neurotransmitter is released from presynaptic neuron into the synaptic cleft via exocytosis.

Question 9

What happens when the neurotransmitter is released into the synaptic cleft?

Answer 9

The neurotransmitter binds to receptor molecules, called ligand gated ion channels, on the postsynaptic membrane

Question 10

What is a ligand?

Answer 10

A chemical messenger

Question 11

What happens when the neurotransmitter binds to the ligand gated ion channel?

Answer 11

Opening or closing of postsynaptic ion channels (for example if Na + channels are opened, Na + ions will enter the postsynaptic neuron and depolarize the neuron, possibly initiating an action potential).

Question 12

What happens when the ligand gated ion channels open or close?

Answer 12

The membrane potential of postsynaptic neuron changes (for example, depolarized if sodium channels are opened), which affects whether the postsynaptic cell may have an action potential.

Question 13

What happens when the membrane potential of the ligand gated ion channels changes?

Answer 13

The vesicular membrane is retrieved from the plasma membrane of the presynaptic neuron

Question 14

What is acetylcholine?

Answer 14

created in the axon terminal by combining choline with an acetyl group (derived from mitochondrial Acetyl CoA)

Question 15

What two classes of specific receptors does acetylcholine bind to?

Answer 15

Nicotinic and muscarinic

Question 16

What happens when there is too much acetylcholine in the synapse?

Answer 16

Fatal seizures and paralysis

Question 17

What breaks down acetylcholine into its two components

Answer 17

Acetylcholinesterase(AchE)

Question 18

Where does the liberated choline return to?

Answer 18

The presynaptic neuron where it is coupled with another acetate to reform acetylcholine