Synaptic Transmission and Action Potential Quiz

At resting potential, the inside of the neuron is:

• Positive

• Negative

• Neutral

• Equal charge inside and outside

What is the charge of a neuron at resting potential?

• –55 mV

• –80 mV

• –70 mV

• +30 mV

During resting potential, which channels are closed?

• Na⁺ only

• K⁺ only

• Na⁺ and K⁺

• Ca²⁺

What triggers depolarization?

• K⁺ channels closing

• Stimulus reaching –55 mV

• Sodium-potassium pump shuts off

• Neurotransmitter release

During depolarization, which ion rushes INTO the neuron?

• Potassium (K⁺)

• Sodium (Na⁺)

• Calcium (Ca²⁺)

• Chloride (Cl⁻)

Depolarization causes the inside of the neuron to become:

• More negative

• More positive

• Neutral

• Unchanged

What membrane charge is reached at peak depolarization?

• –80 mV

• –55 mV

• +30 mV

• 0 mV

What happens first in repolarization?

• Potassium channels close

• Sodium channels open

• Sodium channels close, Potassium channels open

• Ca²⁺ floods the axon

During repolarization, which ion rushes OUT of the neuron?

• Ca²⁺

• Na⁺

• K⁺

• Cl⁻

Repolarization returns the neuron to approximately:

• –55 mV

• –70 mV

• –80 mV

• +30 mV