Action Potential

Question 1

Membrane Potential

Answer 1

Difference in electrical charge between the inside and the outside of a neuron

Question 2

Differences in electrical charges in environment are a result of

Answer 2

ion groupings in the inside and outside of membrane

Question 3

What ions are involved producing action potentials?

Answer 3

Na+ Sodium ions
K- Potassium ions

Question 4

In the neuron, are negatively-charged ions or positively-charged ions more prevalent in the inside at rest?

Answer 4

Negatively-charged
Membrane potential: -70mv

Question 5

Sodium-Potassium Pump

Answer 5

Maintains negative membrane potential
Constantly pumps three Na+ outside the neuon, and pumps 2 K- into the cell

Question 6

Depolarization

Answer 6

Neurotransmitters bind to receptors on the dendrites of the receiving neuron, thus producing a reaction

The membrane becomes LESS polarized (Diffeence i charge decreases)

Question 7

Threshold (Depolarization)

Answer 7

-55v
When the threshold is reached, Sodium channels open which allows Na+ to enter the cell

Rising phase: Membrane potential reaches 0 and becomes positive

Influx of positive ions creates the electrical signal–action potential

Question 8

Repolarization

Answer 8

Action potential reahed peak

Na+ channels close
K- channel open

negatively charged ions flow into neuron

“Falling phase”

Neuron return to resting potential

becomes way more negative originlly, shoots all the way down–hyperpolarization “Refractory Period”

Question 9

Refractory Period

Answer 9

Difficult for neurons to fire again
K- channels close and membrane returns to resting membrane potential