Movement across an unmyelinated Neurone

Question 1

How does movement across an unmyelinated neurone work?

Answer 1

• When Na+ moves into the cells during depolarisation, this triggers an action potential in that section of the neuron
• The Na+ inside the cell will then move down the neurons to the next section of the axon by diffusion
• The Na+ then causes the Na+ channels in that section to open by positive feedback
• If the depolarisation is sufficient to reach the threshold potential, an action potential will then occur here.
• This will continue all the way down the axon
• the diffusion of the Na+ across the axon is called LOCAL CURRENT
• this also causes the nerve impulse to be unidirectional
• The previous bit of the axon is going through the refractory period, so the nerve impulse must carry forward.

Question 2

What is a local current?

Answer 2

• the diffusion of the Na+ across the axon is called local current