HAP9.2b Action Potentials

When a neuron is depolarized, what are the first channels to open?

• Sodium
• Potassium
• Calcium
• ACTH

When a neuron is resting, the inside of the axon has a ____________ charge.

• -55 mV
• -70 mV
• 40 mV
• -75 mV

When a neuron is not engaged in an impulse.

• Resting potential
• Action potential
• Neural potential
• Synaptic potential

Which ions are involved in the electrical nerve impulse?

• Iodine and Sodium
• Potassium and Sodium
• Iron and Sodium
• Calcium and Iodine

What number on the graph represents the Depolarization phase?

• 1
• 2
• 3
• 4

What number on the graph represents the Hyperpolarization phase?

• 1
• 2
• 3
• 4

The sodium-potassium pump....

• Sends (Na⁺) into the cell
• Sends (K⁺) into the cell
• Exchanges (K⁺) & (Na⁺) during depolarization
• Exchanges (K⁺) & (Na⁺) during hyperpolarization

Why is -55 mV a significant number?

• This is the largest charge achieved during an action potential
• This is the threshold required to complete an action potential
• This is the resting charge of a neuron
• This is the charge when all the sodium is inside the cell

Why is hyperpolarization important?

• It makes sure the neuron is healthy
• It prevents a second, unwanted signal from being sent
• It makes sure the neurons are in the correct space
• It makes sure the charge is back at -70 mV

At what stages do Sodium/Potassium Channels open?

• Repolarization/ Repolarization
• Depolarization/ Hyperpolarization
• Hyperpolarization/ Repolarization
• Depolarization/ Repolarization