Neuronal Potentials and Action Potentials Quiz

What is the primary role of the sodium-potassium pump in maintaining the resting potential of a neuron?

• To depolarize the neuron

• To open voltage-gated channels

• To transfer three sodium ions out and two potassium ions in

• To allow free flow of ions across the membrane

Which type of synaptic potential makes it more likely for a neuron to fire an action potential?

• Excitatory postsynaptic potential (EPSP)

• Resting potential

• Graded potential

• Inhibitory postsynaptic potential (IPSP)

At what membrane potential does an action potential typically begin?

• -70 millivolts

• 0 millivolts

• -55 millivolts

• +30 millivolts

During which phase of an action potential do voltage-gated sodium channels close and potassium channels open?

• Resting potential

• Hyperpolarization

• Depolarization

• Repolarization

What prevents an action potential from traveling backward along an axon?

• The size of the axon

• The refractory period

• The presence of myelin sheaths

• The sodium-potassium pump

What is the function of myelin sheaths in neurons?

• To generate action potentials

• To release neurotransmitters

• To insulate the axon and speed up transmission

• To slow down action potential propagation

Where do action potentials occur in myelinated neurons?

• At the axon terminal

• At the nodes of Ranvier

• Only at the axon hillock

• Along the entire axon

Which cells are responsible for creating myelin sheaths in the central nervous system?

• Astrocytes

• Oligodendrocytes

• Microglia

• Schwann cells

What triggers the release of neurotransmitters at the axon terminal?

• Opening of voltage-gated sodium channels

• Opening of voltage-gated calcium channels

• Depolarization of the postsynaptic neuron

• Repolarization of the axon

What happens to neurotransmitters after they are released into the synaptic cleft?

• They are absorbed by the axon terminal

• They trigger an action potential in the presynaptic neuron

• They attach to receptors on the postsynaptic neuron

• They are broken down by enzymes