Question 1

Which of the following best describes the role of myelin in the propagation of an action potential along an axon?

Accepted Answer

Myelin increases the speed of action potential propagation by allowing the action potential to jump between nodes of Ranvier.

Question 2

A neuron has a resting membrane potential of approximately $$-70\ \mathrm{mV}. $$What causes the membrane potential to become more positive during an action potential?

Accepted Answer

Opening of sodium channels allowing $$Na^+ to $$enter the cell.

Question 3

Which of the following scenarios best illustrates spatial summation in neuronal integration?

Accepted Answer

Multiple presynaptic neurons fire simultaneously, and their combined input brings the postsynaptic neuron to threshold.

Question 4

Which neurotransmitter is associated with inhibitory postsynaptic potentials (IPSPs) and is facilitated by ethanol (alcohol)?

Accepted Answer

GABA

Question 5

What is the primary effect of cocaine on synaptic transmission?

Accepted Answer

It blocks the reuptake of dopamine, increasing its concentration in the synaptic cleft.

Question 6

If a postsynaptic neuron receives both excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs), what determines whether it will fire an action potential?

Accepted Answer

The sum of all EPSPs and IPSPs, and whether the membrane potential reaches threshold.

Question 7

Which of the following best describes the 'all-or-none' principle of action potentials?

Accepted Answer

An action potential is only generated if the membrane potential reaches threshold; otherwise, none occurs.

Question 8

Which of the following is NOT a function of the central nervous system (CNS)?

Accepted Answer

Transmitting signals between peripheral nerves and ganglia

Question 9

A drug that blocks the reuptake of neurotransmitters at the synapse would most likely:

Accepted Answer

Increase the concentration of neurotransmitter in the synaptic cleft, prolonging postsynaptic effects.

Question 10

Which of the following correctly matches the neuron type with its primary function?

Accepted Answer

Interneuron: connects sensory and motor neurons within the CNS

Question 11

During the generation of an action potential, which ion movement is primarily responsible for the depolarization phase?

Accepted Answer

$$Na^+$$ ions moving into the cell

Question 12

Which process is responsible for terminating the postsynaptic potential?

Accepted Answer

Destruction or reuptake of neurotransmitters by the axonal terminal

Question 13

A patient is given a drug that keeps inhibitory ion channels open for longer periods on the postsynaptic membrane. What is the most likely effect?

Accepted Answer

Decreased likelihood of action potential generation due to prolonged hyperpolarization

Question 14

Which of the following best describes temporal summation?

Accepted Answer

A single presynaptic neuron fires rapidly in succession, causing postsynaptic potentials to add up.

Question 15

Which of the following is a correct sequence of events in synaptic transmission?

Accepted Answer

Depolarization of presynaptic membrane → release of neurotransmitters → stimulation of postsynaptic receptors

Question 16

Which of the following would most likely result from a loss of myelin in the nervous system, as seen in multiple sclerosis?

Accepted Answer

Slower and less efficient transmission of nerve impulses

Question 17

Which of the following best explains why a neuron may not fire an action potential even when it receives multiple excitatory inputs?

Accepted Answer

The sum of excitatory and inhibitory inputs does not reach the threshold potential.

Question 18

Which of the following terms describes the process by which multiple neurons send signals to a single postsynaptic neuron?

Accepted Answer

Convergence

Question 19

A neuron receives the following synaptic inputs: two EPSPs of $$+10\ \mathrm{mV}$$ each and one IPSP of $$-15\ \mathrm{mV}. If $$the resting membrane potential is $$-70\ \mathrm{mV}$$ and the threshold is $$-50\ \mathrm{mV}$$, will the neuron fire an action potential?

Accepted Answer

No, because the net change brings the membrane potential to $$-65\ \mathrm{mV}$$, below threshold.

Information Transmission in the Nervous System: Foundations of Motor Control

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