BIO 201 Exam 3 V2 | BIO 201 A&P |
StraighterLine | Q&A with Rationale (BIO
201 Exam 3)
1. Which type of neuroglial cell is responsible for forming the myelin sheath around axons in
the Central Nervous System (CNS)?
A. Schwann cells
B. Astrocytes
C. Microglia
D. Oligodendrocytes
Answer: D
Rationale: Oligodendrocytes are the specific glial cells that provide insulation to axons in
the CNS by producing myelin. Schwann cells perform a similar function but are located
exclusively in the Peripheral Nervous System. Astrocytes and microglia serve support and
immune functions respectively, rather than myelination.
2. During the depolarization phase of an action potential, which of the following events
occurs?
A. Potassium ions move out of the cell
B. Sodium ions move into the cell
C. The sodium-potassium pump stops working
,D. The membrane potential becomes more negative
Answer: B
Rationale: Depolarization is triggered when voltage-gated sodium channels open, allowing
sodium ions to rush into the cell due to the electrochemical gradient. This influx of positive
charge makes the internal environment of the neuron less negative relative to the outside.
Potassium exit occurs later during the repolarization phase to restore the resting state.
3. The primary somatosensory cortex is located in which specific region of the brain?
A. Precentral gyrus of the frontal lobe
B. Superior temporal gyrus
C. Postcentral gyrus of the parietal lobe
D. Occipital lobe
Answer: C
Rationale: The postcentral gyrus in the parietal lobe is the site of the primary
somatosensory cortex where tactile information is processed. The precentral gyrus, by
contrast, houses the primary motor cortex responsible for voluntary movement. Temporal
and occipital lobes are primarily associated with auditory and visual processing
respectively.
4. Which part of the brain acts as a relay station for almost all sensory information ascending
to the cerebral cortex?
A. Hypothalamus
, B. Cerebellum
C. Pons
D. Thalamus
Answer: D
Rationale: The thalamus serves as the gateway to the cerebral cortex, filtering and
directing sensory impulses to the appropriate functional areas. The hypothalamus is more
focused on visceral control and endocrine regulation. The pons and cerebellum are
involved in respiratory rhythm and motor coordination respectively.
5. Which division of the Autonomic Nervous System (ANS) is characterized by the ‘fight or
flight’ response?
A. Parasympathetic division
B. Somatic nervous system
C. Enteric nervous system
D. Sympathetic division
Answer: D
Rationale: The sympathetic division prepares the body for stressful or emergency
situations by increasing heart rate and diverting blood to muscles. This is contrasted by the
parasympathetic division, which promotes ‘rest and digest’ activities. The somatic system
controls voluntary skeletal muscles rather than involuntary visceral responses.
StraighterLine | Q&A with Rationale (BIO
201 Exam 3)
1. Which type of neuroglial cell is responsible for forming the myelin sheath around axons in
the Central Nervous System (CNS)?
A. Schwann cells
B. Astrocytes
C. Microglia
D. Oligodendrocytes
Answer: D
Rationale: Oligodendrocytes are the specific glial cells that provide insulation to axons in
the CNS by producing myelin. Schwann cells perform a similar function but are located
exclusively in the Peripheral Nervous System. Astrocytes and microglia serve support and
immune functions respectively, rather than myelination.
2. During the depolarization phase of an action potential, which of the following events
occurs?
A. Potassium ions move out of the cell
B. Sodium ions move into the cell
C. The sodium-potassium pump stops working
,D. The membrane potential becomes more negative
Answer: B
Rationale: Depolarization is triggered when voltage-gated sodium channels open, allowing
sodium ions to rush into the cell due to the electrochemical gradient. This influx of positive
charge makes the internal environment of the neuron less negative relative to the outside.
Potassium exit occurs later during the repolarization phase to restore the resting state.
3. The primary somatosensory cortex is located in which specific region of the brain?
A. Precentral gyrus of the frontal lobe
B. Superior temporal gyrus
C. Postcentral gyrus of the parietal lobe
D. Occipital lobe
Answer: C
Rationale: The postcentral gyrus in the parietal lobe is the site of the primary
somatosensory cortex where tactile information is processed. The precentral gyrus, by
contrast, houses the primary motor cortex responsible for voluntary movement. Temporal
and occipital lobes are primarily associated with auditory and visual processing
respectively.
4. Which part of the brain acts as a relay station for almost all sensory information ascending
to the cerebral cortex?
A. Hypothalamus
, B. Cerebellum
C. Pons
D. Thalamus
Answer: D
Rationale: The thalamus serves as the gateway to the cerebral cortex, filtering and
directing sensory impulses to the appropriate functional areas. The hypothalamus is more
focused on visceral control and endocrine regulation. The pons and cerebellum are
involved in respiratory rhythm and motor coordination respectively.
5. Which division of the Autonomic Nervous System (ANS) is characterized by the ‘fight or
flight’ response?
A. Parasympathetic division
B. Somatic nervous system
C. Enteric nervous system
D. Sympathetic division
Answer: D
Rationale: The sympathetic division prepares the body for stressful or emergency
situations by increasing heart rate and diverting blood to muscles. This is contrasted by the
parasympathetic division, which promotes ‘rest and digest’ activities. The somatic system
controls voluntary skeletal muscles rather than involuntary visceral responses.
