Action Potential (nerve impulses)

Question 1

What is a resting potential ?

Answer 1

When the neuron is at rest, there is a negative charge inside the neuron compared to the outside

Question 2

Action potential

Answer 2

-caused by the distribution of Na+ and K+ ions = regulated by the sodium potassium pump
-the sending of a nerve impulse from dendrites to axon terminals within one neuron
-ions must pass through proteins called ion channels that span the membrane
-ion channels change structure in response to voltage changes=voltage-gated channels

Question 3

Stage 1 of an action potential - Stimulus

Answer 3

-triggers sodium ion channels in the membrane to open allowing sodium ions to diffuse into the neuron down an electrochemical gradient
-when a large enough stimuli is detected, the resting potential can be converted into an action potential

Question 4

Stage 2 - Depolarisation

Answer 4

-action potential is stimulated
-voltage-gated sodium ions channels in the axon membrane open
-sodium ions pass into axon down electrochemical gradient
-more channels open, sodium ions are allowed to enter causing more depolarisation