Question 1

Which of the following best describes the three stages in the processing of information by nervous systems?

Accepted Answer

Sensory input, integration, and motor output

Question 2

A patient suffers a spinal cord injury that disrupts interneurons but leaves sensory and motor neurons intact. Which function is most likely to be impaired?

Accepted Answer

Integration and processing of sensory information

Question 3

Which part of a neuron is primarily responsible for receiving incoming signals from other neurons?

Accepted Answer

Dendrite

Question 4

The resting potential of a neuron is typically between $$-60$$ and $$-80 mV. $$Which of the following best explains why this is the case?

Accepted Answer

There is a higher concentration of $$\mathrm{K^+}$$ inside the cell and $$\mathrm{Na^+}$$ outside, with selective permeability to $$\mathrm{K^+}.$$

Question 5

Which equation can be used to calculate the equilibrium potential for a particular ion across a membrane?

Accepted Answer

$$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{outside}}{[ion]_{inside}} \right)$$

Question 6

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

Accepted Answer

It actively transports $$3\ \mathrm{Na^+}$$ out and $$2\ \mathrm{K^+} in$$, maintaining concentration gradients.

Question 7

Which of the following best distinguishes a graded potential from an action potential?

Accepted Answer

Graded potentials decrease with distance, while action potentials are propagated without loss of amplitude.

Question 8

During the repolarizing phase of an action potential, which two main factors are responsible for returning the membrane potential toward the resting value?

Accepted Answer

Inactivation of voltage-gated $$\mathrm{Na^+}$$ channels and opening of voltage-gated $$\mathrm{K^+}$$ channels

Question 9

Saltatory conduction is a process that:

Accepted Answer

Allows action potentials to jump from one node of Ranvier to the next, increasing conduction speed.

Question 10

A toxin blocks voltage-gated $$\mathrm{Na^+}$$ channels in neurons. What is the most immediate effect on neuronal signaling?

Accepted Answer

Action potentials cannot be initiated.

Question 11

Which of the following best describes the difference between electrical and chemical synapses?

Accepted Answer

Electrical synapses transmit signals via gap junctions, while chemical synapses use neurotransmitters.

Question 12

Which sequence correctly describes the transmission of a signal across a chemical synapse?

Accepted Answer

Action potential arrives at axon terminal $$\rightarrow$$ voltage-gated $$\mathrm{Ca$$^{2+}$$}$$ channels open $$\rightarrow$$ neurotransmitter released $$\rightarrow$$ postsynaptic receptor activation

Question 13

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

Accepted Answer

The sum of all EPSPs and IPSPs at the axon hillock

Question 14

Temporal summation in a neuron refers to:

Accepted Answer

A single synapse firing repeatedly in rapid succession

Question 15

Which neurotransmitter is most directly associated with muscle contraction at vertebrate neuromuscular junctions?

Accepted Answer

Acetylcholine

Question 16

Which of the following amino acids acts as the main inhibitory neurotransmitter in the mammalian central nervous system?

Accepted Answer

GABA (gamma-aminobutyric acid)

Question 17

Nitric oxide ($$\mathrm{NO}) $$and carbon monoxide ($$\mathrm{CO}) $$are unique among neurotransmitters because they:

Accepted Answer

Act as local regulators and diffuse directly across cell membranes

Question 18

A patient is given a drug that increases the permeability of the neuronal membrane to $$\mathrm{K^+} at $$rest. What is the most likely effect on the resting membrane potential?

Accepted Answer

The resting potential becomes more negative (hyperpolarizes).

Question 19

Which adaptation would most likely increase the speed of action potential propagation along an axon?

Accepted Answer

Increasing axon diameter and adding a myelin sheath

Question 20

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

Accepted Answer

The time during which the neuron is hyperpolarized and cannot generate another action potential

Neurons, Synapses, and Signaling: Study Guide

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