BIOD 152 MODULE 1 ACTUAL EXAM 2025/2026 | Portage
Learning | 26 Questions with Rationales | Complete Answer Key |
Pass Guaranteed - A+ Graded
Q1: Which of the following correctly describes the structural organization of the nervous
system?
A. The CNS consists only of the brain, while the PNS consists of the spinal cord and all
neural pathways outside the brain.
B. The autonomic nervous system is a subdivision of the central nervous system
responsible for involuntary control.
C. The CNS consists of the brain and spinal cord, while the PNS consists of all neural
structures outside the CNS, including cranial nerves, spinal nerves, and ganglia.
[CORRECT]
D. The somatic nervous system controls involuntary functions such as heart rate and
digestion.
Correct Answer: C
Rationale: The nervous system is structurally divided into the central nervous system
(CNS) and peripheral nervous system (PNS). The CNS comprises the brain and spinal
cord, which serve as the integration and command centers. The PNS includes all neural
structures outside the CNS—cranial nerves (12 pairs), spinal nerves (31 pairs), sensory
receptors, and ganglia (clusters of neuron cell bodies). Distractor A is incorrect because
it excludes the spinal cord from the CNS. Distractor B is incorrect because the
autonomic nervous system is part of the PNS, not the CNS; the CNS contains only brain
,and spinal cord tissue. Distractor D is incorrect because the somatic nervous system
controls voluntary skeletal muscle movement and conscious sensory perception,
whereas the autonomic nervous system controls involuntary functions. This
organizational framework is fundamental to understanding how sensory information
reaches the CNS and how motor commands are executed.
Q2 (Short Answer): List the three main functional divisions of the peripheral nervous
system (PNS) and briefly describe the primary function of each division.
Correct Answer:
1. Sensory (Afferent) Division – Transmits sensory information from receptors to
the CNS.
2. Motor (Efferent) Division – Transmits motor commands from the CNS to
effectors (muscles and glands).
3. Autonomic Nervous System (further divided into sympathetic and
parasympathetic) – Controls involuntary functions of visceral organs, smooth
muscle, and glands. [CORRECT]
Note: Acceptable alternative organization may group Motor into Somatic and
Autonomic divisions.
Rationale: The PNS is functionally organized based on information flow direction and
target effectors. The sensory/afferent division carries impulses toward the CNS from
sensory receptors (exteroceptors, interoceptors, proprioceptors). The motor/efferent
division carries impulses away from the CNS to effector organs. The motor division is
further subdivided into the somatic nervous system (voluntary control of skeletal
muscles) and the autonomic nervous system (involuntary control of cardiac muscle,
smooth muscle, and glands). The autonomic division is then divided into sympathetic
(fight-or-flight responses) and parasympathetic (rest-and-digest responses) branches.
Full credit requires identifying the sensory division, distinguishing motor output
pathways, and recognizing the involuntary nature of autonomic control.
, Q3 (True/False): The myelin sheath is produced by oligodendrocytes in the peripheral
nervous system and by Schwann cells in the central nervous system.
Correct Answer: False [CORRECT]
Rationale: This statement reverses the locations of these neuroglial cells. Schwann
cells produce myelin in the PNS, wrapping around a single axon segment of one neuron
and forming the neurolemma (sheath of Schwann), which is essential for nerve
regeneration. Oligodendrocytes produce myelin in the CNS, but unlike Schwann cells,
each oligodendrocyte can myelinate multiple axons (up to 60) simultaneously.
Additionally, CNS myelin lacks a neurolemma, which explains why CNS axons have
limited regenerative capacity compared to PNS axons. This distinction is clinically
significant in demyelinating diseases: multiple sclerosis affects CNS oligodendrocytes,
while Guillain-Barré syndrome affects PNS Schwann cells.
Q4: During the generation of an action potential, which ion movement is primarily
responsible for the depolarization phase?
A. Efflux of K⁺ ions through voltage-gated potassium channels
B. Influx of Na⁺ ions through voltage-gated sodium channels [CORRECT]
C. Influx of Ca²⁺ ions through voltage-gated calcium channels
D. Efflux of Cl⁻ ions through ligand-gated chloride channels
Correct Answer: B
Rationale: The depolarization phase of an action potential is characterized by rapid
influx of Na⁺ ions through opened voltage-gated sodium channels. When the membrane
potential reaches threshold (approximately -55 mV), these channels open, allowing Na⁺
Learning | 26 Questions with Rationales | Complete Answer Key |
Pass Guaranteed - A+ Graded
Q1: Which of the following correctly describes the structural organization of the nervous
system?
A. The CNS consists only of the brain, while the PNS consists of the spinal cord and all
neural pathways outside the brain.
B. The autonomic nervous system is a subdivision of the central nervous system
responsible for involuntary control.
C. The CNS consists of the brain and spinal cord, while the PNS consists of all neural
structures outside the CNS, including cranial nerves, spinal nerves, and ganglia.
[CORRECT]
D. The somatic nervous system controls involuntary functions such as heart rate and
digestion.
Correct Answer: C
Rationale: The nervous system is structurally divided into the central nervous system
(CNS) and peripheral nervous system (PNS). The CNS comprises the brain and spinal
cord, which serve as the integration and command centers. The PNS includes all neural
structures outside the CNS—cranial nerves (12 pairs), spinal nerves (31 pairs), sensory
receptors, and ganglia (clusters of neuron cell bodies). Distractor A is incorrect because
it excludes the spinal cord from the CNS. Distractor B is incorrect because the
autonomic nervous system is part of the PNS, not the CNS; the CNS contains only brain
,and spinal cord tissue. Distractor D is incorrect because the somatic nervous system
controls voluntary skeletal muscle movement and conscious sensory perception,
whereas the autonomic nervous system controls involuntary functions. This
organizational framework is fundamental to understanding how sensory information
reaches the CNS and how motor commands are executed.
Q2 (Short Answer): List the three main functional divisions of the peripheral nervous
system (PNS) and briefly describe the primary function of each division.
Correct Answer:
1. Sensory (Afferent) Division – Transmits sensory information from receptors to
the CNS.
2. Motor (Efferent) Division – Transmits motor commands from the CNS to
effectors (muscles and glands).
3. Autonomic Nervous System (further divided into sympathetic and
parasympathetic) – Controls involuntary functions of visceral organs, smooth
muscle, and glands. [CORRECT]
Note: Acceptable alternative organization may group Motor into Somatic and
Autonomic divisions.
Rationale: The PNS is functionally organized based on information flow direction and
target effectors. The sensory/afferent division carries impulses toward the CNS from
sensory receptors (exteroceptors, interoceptors, proprioceptors). The motor/efferent
division carries impulses away from the CNS to effector organs. The motor division is
further subdivided into the somatic nervous system (voluntary control of skeletal
muscles) and the autonomic nervous system (involuntary control of cardiac muscle,
smooth muscle, and glands). The autonomic division is then divided into sympathetic
(fight-or-flight responses) and parasympathetic (rest-and-digest responses) branches.
Full credit requires identifying the sensory division, distinguishing motor output
pathways, and recognizing the involuntary nature of autonomic control.
, Q3 (True/False): The myelin sheath is produced by oligodendrocytes in the peripheral
nervous system and by Schwann cells in the central nervous system.
Correct Answer: False [CORRECT]
Rationale: This statement reverses the locations of these neuroglial cells. Schwann
cells produce myelin in the PNS, wrapping around a single axon segment of one neuron
and forming the neurolemma (sheath of Schwann), which is essential for nerve
regeneration. Oligodendrocytes produce myelin in the CNS, but unlike Schwann cells,
each oligodendrocyte can myelinate multiple axons (up to 60) simultaneously.
Additionally, CNS myelin lacks a neurolemma, which explains why CNS axons have
limited regenerative capacity compared to PNS axons. This distinction is clinically
significant in demyelinating diseases: multiple sclerosis affects CNS oligodendrocytes,
while Guillain-Barré syndrome affects PNS Schwann cells.
Q4: During the generation of an action potential, which ion movement is primarily
responsible for the depolarization phase?
A. Efflux of K⁺ ions through voltage-gated potassium channels
B. Influx of Na⁺ ions through voltage-gated sodium channels [CORRECT]
C. Influx of Ca²⁺ ions through voltage-gated calcium channels
D. Efflux of Cl⁻ ions through ligand-gated chloride channels
Correct Answer: B
Rationale: The depolarization phase of an action potential is characterized by rapid
influx of Na⁺ ions through opened voltage-gated sodium channels. When the membrane
potential reaches threshold (approximately -55 mV), these channels open, allowing Na⁺
