Axon Conduction lecture 14

Action Potential spreads down the axon by

Sodium Channels inactivate quickly

Potassium Channels slowly activated (restore charge)

sodium (Na+) depolarized the membrane

when a local anesthesia is given what happens

the channel is blocked and sodium ion is unable to pass through causing no action potentials

how do neurons get the action potential to the next neuron

unmyelinated axon and myelinated axon

what are unmyelinated axons?

voltage-gated Na+ and K+ channels regenerate the action potential at each point along the axon, so voltage does not decay

what are myelinated axons?

myelin keeps current in axons (voltage doesn’t decay much). APs are generated only in the nodes of Ranvier and appear to ”jump” rapidly from node to node

myelinated axon and unmyelinated axon which is slow and why

Unmyelinated axon is slow because movements of ions and of the gates of channel proteins take time and must occur before voltage regeneration occurs

what is myelin?

fats and proteins (insulator)

what are Saltatory conduction

“Jump” from node to node. Sodium channels only at nodes

What happens if myelin degenerates?

Loss of motor function

what is multiple sclerosis

it is an autoimmune disease where the Immune cells destroy myelin sheaths

what are some non destructive ways to slow nerves impulses

Pressure restricts blood flow

Cold redirects blood flow

what are other strategies to prevent current decline

large axon size because it have less resistance

if all action potentials are alike then how does our brain and body know the differences?

the intensity coded by the frequency is how the difference is known.