What is the basic unit of communication in the nervous system?

• Neuron

• Muscle cell

• Blood cell

• Axon

What is the term used to describe the electrical impulse that neurons fire?

• Resistance

• Current

• Voltage

• Action potential

What can neurons vary to communicate different messages?

• Temperature of the impulse

• Size of the neuron

• Color of the signal

• Frequency of pulses

What is the resting membrane potential of a neuron?

• +40 millivolts

• -70 millivolts

• 0 millivolts

• -55 millivolts

What type of channels open at certain membrane potentials?

• Voltage-gated channels

• Thermally gated channels

• Mechanically gated channels

• Ligand-gated channels

What is the role of the sodium-potassium pump?

• Maintains the electrochemical gradient

• Generates action potentials

• Absorbs nutrients

• Produces neurotransmitters

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What happens when a neuron's membrane potential reaches the threshold of -55 mV?

• The neuron dies

• The neuron divides

• The neuron goes to sleep

• An action potential is triggered

What is the process called when the neuron becomes more positive and reaches about +40 mV?

• Polarization

• Hyperpolarization

• Repolarization

• Depolarization

What affects a neuron's transmission speed the most?

• Size of the neuron

• Number of synapses

• Length of the axon

• Myelin sheath

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

• Prevents signals from traveling in both directions

• Generates more action potentials

• Restores the neuron to its resting state

• Increases the neuron's speed