MCAT Biology Practice Test 4: The Nervous System

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1. Resting membrane potential depends on:

differential distribution of ions across the axon membrane.

the opening of voltage-gated calcium channels.

active transport of ions across the membrane.

  • A. I only
  • B. I and II only
  • C. I and III only
  • D. II and III only

2. All of the following are associated with the myelin sheath EXCEPT:

  • A. faster conduction of nerve impulses.
  • B. nodes of Ranvier forming gaps along the axon.
  • C. increased magnitude of the potential difference during an action potential.
  • D. saltatory conduction of action potentials.

3. Which of the following is true with regard to the action potential?

  • A. All hyperpolarized stimuli will be carried to the axon terminal without a decrease in size.
  • B. The size of the action potential is proportional to the size of the stimulus that produced it.
  • C. Increasing the intensity of the depolarization increases the size of the impulse.
  • D. Once an action potential is triggered, an impulse of a given magnitude and speed is produced.

4. Which of the following correctly describes a difference between nerves and tracts?

  • A. Nerves are seen in the central nervous system; tracts are seen in the peripheral nervous system.
  • B. Nerves have cell bodies in nuclei; tracts have cell bodies in ganglia.
  • C. Nerves may carry more than one type of information; tracts can only carry one type of information.
  • D. Nerves contain only one neuron; tracts contain many neurons.

5. Which of the following accurately describes sensory neurons?

  • A. Sensory neurons are afferent and enter the spinal cord on the dorsal side.
  • B. Sensory neurons are efferent and enter the spinal cord on the dorsal side.
  • C. Sensory neurons are afferent and enter the spinal cord on the ventral side.
  • D. Sensory neurons are efferent and enter the spinal cord on the ventral side.

6. When a sensory neuron receives a stimulus that brings it to threshold, it will do all of the following EXCEPT:

  • A. become depolarized.
  • B. transduce the stimulus to an action potential.
  • C. inhibit the spread of the action potential to other sensory neurons.
  • D. cause the release of neurotransmitters onto cells in the central nervous system.

7. When the potential across the axon membrane is more negative than the normal resting potential, the neuron is said to be in a state of:

  • A. depolarization.
  • B. hyperpolarization.
  • C. repolarization.
  • D. polarization.

8. Which of the following statements concerning the somatic division of the peripheral nervous system is INCORRECT?

  • A. Its pathways innervate skeletal muscle.
  • B. Its pathways are usually voluntary.
  • C. Some of its pathways are referred to as reflex arcs.
  • D. Its pathways always involve more than two neurons.

9. Which of the following is a function of the parasympathetic nervous system?

  • A. Increasing blood sugar during periods of stress
  • B. Dilating the pupils to enhance vision
  • C. Increasing oxygen delivery to muscles
  • D. Decreasing heart rate and blood pressure

10. Which of the following neurotransmitters is used in the ganglia of both the sympathetic and parasympathetic nervous systems?

  • A. Acetylcholine
  • B. Dopamine
  • C. Norepinephrine
  • D. Serotonin

11. In which neural structure are ribosomes primarily located?

  • A. Dendrites
  • B. Soma
  • C. Axon hillock
  • D. Axon

12. An autoimmune disease attacks the voltage-gated calcium channels in the nerve terminal. What is a likely symptom of this condition?

  • A. Spastic paralysis (inability to relax the muscles)
  • B. Flaccid paralysis (inability to contract the muscles)
  • C. Inability to reuptake neurotransmitters once released
  • D. Retrograde flow of action potentials

13. A neuron only fires an action potential if multiple presynaptic cells release neurotransmitter onto the dendrites of the neuron. This is an example of:

  • A. saltatory conduction.
  • B. summation.
  • C. a feedback loop.
  • D. inhibitory transmission.

14. A disease results in the death of Schwann cells. Which portion of the nervous system is NOT likely to be affected?

  • A. Central nervous system
  • B. Somatic nervous system
  • C. Autonomic nervous system
  • D. Parasympathetic nervous system

15. A surgeon accidentally clips a dorsal root ganglion during a spinal surgery. What is a likely consequence of this error?

Loss of motor function at that level

Loss of sensation at that level

Loss of cognitive function

  • A. I only
  • B. II only
  • C. I and II only
  • D. I, II, and III