BIO 201 Exam 4 V1 | BIO 201 A&P |
StraighterLine | Q&A with Rationale (BIO
201 Exam 4)
1. Which of the following ions is primarily responsible for the depolarization phase of an
action potential?
A. Sodium (Na+)
B. Potassium (K+)
C. Calcium (Ca2+)
D. Chloride (Cl-)
Answer: A
Rationale: Depolarization occurs when voltage-gated sodium channels open, allowing
sodium ions to rush into the cell. This influx of positive charge makes the interior of the
neuron less negative. The rapid change in membrane potential is what characterizes the
upward swing of the action potential graph.
2. Where is the primary motor cortex located in the brain?
A. Postcentral gyrus
B. Temporal lobe
C. Occipital lobe
D. Precentral gyrus
,Answer: D
Rationale: The primary motor cortex is situated in the precentral gyrus of the frontal lobe.
It is responsible for the execution of voluntary movements throughout the body. Each
section of the gyrus controls a specific muscle group on the contralateral side of the body.
3. Which neuroglial cell is responsible for forming the myelin sheath within the central
nervous system (CNS)?
A. Schwann cells
B. Astrocytes
C. Microglia
D. Oligodendrocytes
Answer: D
Rationale: Oligodendrocytes are specialized cells that wrap their cytoplasmic processes
around axons in the brain and spinal cord. One oligodendrocyte can provide myelin for
multiple axons simultaneously. This insulation is crucial for the rapid saltatory conduction
of electrical impulses.
4. The gap between two communicating neurons is called the:
A. Synapse
B. Node of Ranvier
C. Axon hillock
, D. Dendrite
Answer: A
Rationale: The synapse is the functional junction where information is transmitted from a
presynaptic neuron to a postsynaptic cell. It consists of the axon terminal, the synaptic cleft,
and the receptor site on the receiving cell. Neurotransmitters are released into this space to
bridge the electrical signal.
5. Which cranial nerve is primarily responsible for the sense of vision?
A. Cranial Nerve I
B. Cranial Nerve IV
C. Cranial Nerve III
D. Cranial Nerve II
Answer: D
Rationale: Cranial Nerve II is the Optic Nerve, which carries visual information from the
retina to the brain. It passes through the optic canal to reach the optic chiasm. Damage to
this nerve can result in various degrees of visual loss or total blindness.
6. What is the function of the medulla oblongata?
A. Control of vital functions like heart rate and breathing
B. Coordination of skeletal muscle movement
C. Regulation of body temperature
StraighterLine | Q&A with Rationale (BIO
201 Exam 4)
1. Which of the following ions is primarily responsible for the depolarization phase of an
action potential?
A. Sodium (Na+)
B. Potassium (K+)
C. Calcium (Ca2+)
D. Chloride (Cl-)
Answer: A
Rationale: Depolarization occurs when voltage-gated sodium channels open, allowing
sodium ions to rush into the cell. This influx of positive charge makes the interior of the
neuron less negative. The rapid change in membrane potential is what characterizes the
upward swing of the action potential graph.
2. Where is the primary motor cortex located in the brain?
A. Postcentral gyrus
B. Temporal lobe
C. Occipital lobe
D. Precentral gyrus
,Answer: D
Rationale: The primary motor cortex is situated in the precentral gyrus of the frontal lobe.
It is responsible for the execution of voluntary movements throughout the body. Each
section of the gyrus controls a specific muscle group on the contralateral side of the body.
3. Which neuroglial cell is responsible for forming the myelin sheath within the central
nervous system (CNS)?
A. Schwann cells
B. Astrocytes
C. Microglia
D. Oligodendrocytes
Answer: D
Rationale: Oligodendrocytes are specialized cells that wrap their cytoplasmic processes
around axons in the brain and spinal cord. One oligodendrocyte can provide myelin for
multiple axons simultaneously. This insulation is crucial for the rapid saltatory conduction
of electrical impulses.
4. The gap between two communicating neurons is called the:
A. Synapse
B. Node of Ranvier
C. Axon hillock
, D. Dendrite
Answer: A
Rationale: The synapse is the functional junction where information is transmitted from a
presynaptic neuron to a postsynaptic cell. It consists of the axon terminal, the synaptic cleft,
and the receptor site on the receiving cell. Neurotransmitters are released into this space to
bridge the electrical signal.
5. Which cranial nerve is primarily responsible for the sense of vision?
A. Cranial Nerve I
B. Cranial Nerve IV
C. Cranial Nerve III
D. Cranial Nerve II
Answer: D
Rationale: Cranial Nerve II is the Optic Nerve, which carries visual information from the
retina to the brain. It passes through the optic canal to reach the optic chiasm. Damage to
this nerve can result in various degrees of visual loss or total blindness.
6. What is the function of the medulla oblongata?
A. Control of vital functions like heart rate and breathing
B. Coordination of skeletal muscle movement
C. Regulation of body temperature
