Neurons - synaptic transmission

Question 1

What does the cell’s action potential/electrical impulse start as?

Answer 1

Small electrical imoulses generated at axon hillock

When message reaches axon terminal it turns into chemical message

Question 2

What happens when the impulse reaches the axon terminal?

Answer 2

Neuron can pass its chemical message across synaptic gap

Neuron sending message is pre-synaptic neuron
Neuron receiving message is post-synaptic neuron

Question 3

What also happens when the action potential reaches axon terminal (vesicles)?

Answer 3

• Calcium channels open + flood terminal button with calcium ions
• Vesicles containing neurotransmitter will be released + travel down outer membrane of terminal button
• Casing of vesicle will fuse with membrane
• Neurotransmitter released + sent across synaptic gap

Question 4

What happens when neurotransmitters cross the synaptic gap?

Answer 4

Receptors on post-synaptic neuron will bind to specific neurotransmitter + absorb it

Question 5

What happens to neurotransmitters that arent absorbed?

Answer 5

• Will be destroyed by enzymes in synaptic gap

OR

• Be reabsorbed by presynaptic neuron = this is called reuptake

Question 6

Why are reabsorbed enzymes destroyed by enzymes in the neuron?

Answer 6

In order to turn off neuron in prep for future action potential

Question 7

Explain the synaptic transmission process briefly:

Answer 7

1. Action potential
2. Fusion open
3. Neurotransmitter released into synaptic gap
4. Re-uptake (Reabsorb neurotransmitters + repackaged into vesicles)