Question 1

Which of the following best describes the difference between electrical and chemical communication in neurons?

Accepted Answer

Electrical communication happens along the axon as action potentials, while chemical communication occurs at the synapse via neurotransmitters.

Question 2

A neuron at rest has a resting potential of approximately $$-70\ \mathrm{mV}. $$What causes the inside of the neuron to be negatively charged relative to the outside?

Accepted Answer

The selective permeability of the membrane to potassium ions and the action of the sodium-potassium pump.

Question 3

During an action potential, which event occurs first after the threshold is reached?

Accepted Answer

Sodium channels open, allowing $$Na^+ to $$enter the cell.

Question 4

Which of the following best describes the refractory period of a neuron?

Accepted Answer

The time when the neuron cannot fire another action potential, regardless of stimulus strength.

Question 5

If a neuron receives both excitatory and inhibitory signals simultaneously, what determines whether it will fire an action potential?

Accepted Answer

Whether the sum of excitatory signals outweighs the inhibitory signals and the membrane potential reaches threshold.

Question 6

Which neurotransmitter is primarily involved in the brain's reward processing, motivation, and attention?

Accepted Answer

Dopamine

Question 7

Selective Serotonin Reuptake Inhibitors (SSRIs) are used to treat depression. What is their primary mechanism of action?

Accepted Answer

SSRIs block the reuptake of serotonin into the presynaptic neuron, increasing serotonin levels in the synapse.

Question 8

Which of the following is TRUE about the movement of ions during the depolarization phase of an action potential?

Accepted Answer

Sodium ions move into the neuron, making the inside more positive.

Question 9

Which neurotransmitter is the major inhibitory neurotransmitter in the brain?

Accepted Answer

Gamma-aminobutyric acid (GABA)

Question 10

What is the role of specialized receptors on the postsynaptic neuron?

Accepted Answer

To receive and respond to specific neurotransmitters released from the presynaptic neuron.

Question 11

Which process removes leftover neurotransmitters from the synapse by breaking them down chemically?

Accepted Answer

Degradation

Question 12

A neuron’s membrane potential changes from $$-70\ \mathrm{mV} to$$ $$-55\ \mathrm{mV}. $$What is most likely to occur next?

Accepted Answer

An action potential will be triggered if threshold is reached.

Question 13

Which of the following best explains why neurons do not fire continuously?

Accepted Answer

The refractory period prevents immediate re-firing after an action potential.

Question 14

Which neurotransmitter is most closely associated with the 'fight or flight' response?

Accepted Answer

Norepinephrine

Question 15

What is the function of ion channels in the neuron membrane?

Accepted Answer

To allow the movement of sodium and potassium ions in and out of the cell.

Question 16

Which of the following is a correct sequence of events for signal transmission from one neuron to another?

Accepted Answer

Action potential travels down the axon → neurotransmitters released into the synapse → neurotransmitters bind to receptors on the postsynaptic neuron.

Question 17

Which of the following drugs would most likely enhance the inhibitory effect of GABA in the brain?

Accepted Answer

Benzodiazepines

Question 18

What is the main effect of excitatory neurotransmitters on the postsynaptic neuron?

Accepted Answer

They increase the probability of the neuron firing an action potential.

Question 19

Which of the following mechanisms is NOT involved in the removal of neurotransmitters from the synaptic cleft?

Accepted Answer

Active transport of neurotransmitters into the postsynaptic neuron

Question 20

A neuron receives signals from hundreds of other neurons. What determines whether it will generate an action potential?

Accepted Answer

The sum of excitatory and inhibitory inputs at the axon hillock reaching threshold.

Communication in the Nervous System: Electrochemical Signaling and Neurotransmission

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