Essay 1

Question 1

Action Potential

Answer 1

A neuron is stimulated beyond it’s threshold potential, typically around -55mV. This occurs when the neuronstransmitters blind to receptors on the neuron membrane, causing depolarization.

Question 2

Depolarizations

Answer 2

Voltage-gated sodium (Na+) channel open, allowing Na+ ions to rush into the neurons, causing the mebrane potential to become more postive, reaching around +30.

Question 3

Repolarization

Answer 3

After reaching the peak of the action potential, the Na+ channel close and voltage-gated potassim (K+) channel open. This lead to repolarization as K+ ions flow out of the neurons, bringing the membrane potential back down towards resting potential.

Question 4

Hyperpolarization

Answer 4

The membrane potential briefely becomes more negative than the resting potential due to the continued efflux of K+ ions

Question 5

Sodium-Potassium

Answer 5

helps reset the membrane potential by actively transporting Na+ ions of the cell and K+ ions back into the cell, restoring the resting membrane. Potential of approximately -70mV.

Question 6

Down the axon

Answer 6

The action potential propgates down the axon through a process called saltatory conduction in myelinated axons, where the action potential jumps between the nodes of Ranvier, increasing the speed of transmissions.

Question 7

Essay

Describe an action potential from its generation to its movement down an axon. How is the membrane potential reset?

Answer 7

An action potential is generated by depolarization due to Na+ influx, followed by replarization through K+ efflux, Hyperpolarization becomes negative, and the membrane potential is reset by the sodium-potassium pump.