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

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

At what stage does Potassium end outside the neuron, and Sodium ends inside the neuron?

• Depolarizarion
• Repolarization
• Hyperpolarization
• Resting Potential

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

Which ion is pumped into the axon of a neuron to help maintain the resting potential?

• calcium

• hydrogen

• potassium

• sodium

Why is the speed of an impulse increased if a neurone is wrapped in myelin?

• potassium ions flow out of the neurone faster

• myelin insulates the neurone so the temperature increases

• the impulse can jump from node to node

• it allows neurones to touch each other

After depolarization what happens to restore resting potential? 

• Sodium channels open & sodium ions diffuse out of the neuron.
• Potassium channels open & potassium ions diffuse into the neuron.
• Potassium channels open and potassium ions diffuse into the neuron.
• Sodium channels open and sodium ions diffuse into the neuron. 

What describes the phase of quick entry of sodium ions into an axon during an action potential? 

• passive transport
• depolarization
• ion transport
• repolarization