Neuron and Nerve Impulse Quiz

What is the function of the dendrite in a neuron?

• Receive signals from receptors + neurons

• Carry the impulse to be passed along neuron/effector

• Secrete myelin

• Contain neurotransmitters to help nerve impulse travel

What is the role of the myelin sheath in a neuron?

• Contains neurotransmitters to help nerve impulse travel

• Fatty coating in which it regenerates and insulates, protects axon

• Carries the impulse to be passed along neuron/effector

• Receives signals from receptors + neurons

What is the function of the axon terminal in a neuron?

• Regenerates and insulates, protects axon

• Carries the impulse to be passed along neuron/effector

• Receives signals from receptors + neurons

• End of axon, contains neurotransmitters to help nerve impulse travel

What is the purpose of saltatory conduction in a myelinated neuron?

• Receive signals from receptors + neurons

• Increase speed of nerve impulse transmission

• Carry the impulse to be passed along neuron/effector

• Regenerate and insulate, protect axon

What is the membrane potential of a neuron at resting state?

• -50 mV

• -90 mV

• -55 mV

• -70 mV

What is the minimum stimulus required to start a nerve impulse?

• Threshold level = -55 mV

• Threshold level = -70 mV

• Threshold level = -50 mV

• Threshold level = -90 mV

What is the process of depolarization in a neuron?

• Charge becomes more (-) than resting potential

• (+) to a (-) charge due to potassium entering the axon

• Re-establishes the resting membrane potential

• (-) to a (+) charge due to sodium entering the axon

What is the function of the neurotransmitter GABA (inhibitory) in a neuron?

• Stimulates opening of potassium channels

• Binds to sodium channels on postsynaptic membrane

• Causes hyperpolarization

• Increases speed of nerve impulse transmission

What happens when an action potential arrives at the axon terminal of a presynaptic neuron?

• Sodium channels open and depolarization occurs

• Synaptic vesicle fuses to membrane and releases neurotransmitter into the synapse

• Enzyme cholinesterase breaks down any remaining acetylcholine in the synapse

• Potassium gates open and potassium moves out

What is the purpose of the refractory period in a neuron?

• Re-establish the resting membrane potential

• Increase the speed of nerve impulse transmission

• Restore the original ion positions on either side of the membrane

• Re-establish the threshold level for nerve impulse