Action Potential

Question 1

What is the scientific name of a protein?

Answer 1

Amino acid

Question 2

What are the main components of a neuron?

Answer 2

Soma (cellbody), Dendrites, Axon, Axon terminals and synapse

Question 3

What are the main ions in a cell ?

Answer 3

Potassium (K+), Sodium (Na+), Chloride (Cl-) and Calcium (Ca2+)

Question 4

What is the difference between the force of diffusion and the electrostatic force ?

Answer 4

Force of diffusion->only with same ions/want to space out/ move from high concentration to low concentration
Electrostatic force->similar charge ions repeal each other

Question 5

What is charge of the cell at its resting membrane potential?

Answer 5

-70mV

Question 6

What are the two proteins responsible for the resting membrane potential?

Answer 6

1.Sodium-Potassium Pump->Sodium out/potassium in/create a concentration gradient
2.Leak Potassium channel->open door for potassium leaving because of force of diffusion

Question 7

What are the concentration gradients for potassium and sodium in a neuron?

Answer 7

Potassium is 30X more concentrated inside the cell than out
Sodium is 15X more concentrated outside the cell than inside

Question 8

What are the three phases of an action potential?

Answer 8

Depolarization, Overshoot, repolarization

Question 9

What are the three proteins responsible for the action potential?

Answer 9

the voltage-gated sodium channel, the voltage-gated potassium channel, the voltage-gated calcium channel

Question 10

At what voltage do the gates of the voltage-gated sodium channel open?

Answer 10

-55mV (threshold) until +40mV

Question 11

At what voltage do the gates of the voltage-gated potassium channel open?

Answer 11

0mV

Question 12

What is the all-or-none law?

Answer 12

The all-or-none law states that an action potential can either occur or not but once triggered, the action potential is always the same

Question 13

How do a neuron return to its resting membrane potential after an action potential?

Answer 13

Thanks to the Sodium-potassium pump and the Leak potassium channel

Question 14

Why does the neuron have a hyperpolarization period?

Answer 14

The neuron has a hyperpolarization period because the voltage-gated potassium channel are slow to close and therefore, potassium is still leaving the cell.

Question 15

Why is it impossible to trigger a new action potential during the previous one?

Answer 15

Because of the inactivation of the volatge-gated sodium channels during the absolute refractory period.

Question 16

What is the relative refractory period?

Answer 16

This is the period during which voltage-gated sodium channels closed but voltage-gated potassium channels are still open. It required a greater stimulus to cause action potentials to fire.