Neurons - action potential

Question 1

What is action potential?

Answer 1

Refers to method by which nerve impulse passes down axon of neuron to stimulate release of neurotransmitters

Current of energy - Gives energy for neurotransmitters to travel down neuron

Question 2

What causes a spike in electric charge in an axon?

Answer 2

Sodium ions crossing the cell membrane

Each neuron acts as a battery with its own separate charges

Question 3

What is an electrical impulse triggered by?

Answer 3

A change in electrical potential of the neuron

Question 4

What is depolarisation?

Answer 4

Where neurons have resting membrane potential of -70mv, meaning inside of neuron has negative charge + outside has positive charge

Question 5

What happens when an environmental stimulus occurs?

Answer 5

It triggers part of neural membrane to open and allow + charged ions inside cell and - charged ions out

Question 6

What is the charge needed for the channel to open?

Answer 6

-55mv

If charge doesnt hit that level, neuron returns to resting state

Question 7

When does -55mv only occur?

Answer 7

If enough receptors are activated on dendrite + this opens ion channels to allow + charge in to increase neuron to 40mv

Question 8

What happens when charge reaches 40mv?

Answer 8

Impulse is transmitted down nerve fibre

Then this electrical impulse is carried down nerve through series of action potentials

Question 9

When can the action potential only be generated?

Answer 9

When depolarisation reaches a threshold, always same intensity

Its an all or nothing event

Question 10

How does action potential send an impulse along axon of a neuron?

Answer 10

1. When neuron at rest, inside - and outside +
2. Neuron stimulated, + charged particles enter
3. Action potential initiated - neuron depolarised
4. After, some + particles pushed outside neuron and it moves back to polarised state
5. Neuron has returned to initial polarised resting state