Portage Learning A&P 1 Module 6 Lab Exam Nervous System Actual Exam 2026/2027
– Complete 30 Questions with Detailed Rationales | 100% Verified | Pass Guaranteed –
A+ Graded
SECTION A: NERVOUS TISSUE & NEURON ANATOMY (Q1–Q6)
Q1: During the lab practical, a pointer on the neuron model indicates the single, long
cytoplasmic extension that conducts nerve impulses away from the cell body toward an
effector. Which structure is being identified?
A. Dendrite
B. Axon hillock
C. Axon [CORRECT]
D. Chromatophilic (Nissl) substance
Correct Answer: C
Rationale: The axon transmits impulses away from the soma, whereas dendrites
conduct impulses toward it. The axon hillock is only the cone-shaped origin region, and
Nissl substance is rough ER found within the cell body.
Q2: Which type of neuroglial cell forms the myelin sheath around axons within the
central nervous system (CNS)?
A. Schwann cell
B. Satellite cell
C. Microglia
D. Oligodendrocyte [CORRECT]
Correct Answer: D
Rationale: Oligodendrocytes myelinate CNS axons, with each cell wrapping segments of
multiple fibers. Schwann cells myelinate in the PNS, satellite cells support ganglion cell
bodies, and microglia are phagocytes.
Q3: A student examines a longitudinal microscope slide of a myelinated peripheral
nerve fiber and observes small uninsulated gaps between adjacent Schwann cells along
the axon. What physiologically occurs at these nodes of Ranvier?
A. Neurotransmitter is released into the synaptic cleft
B. Action potentials "jump" from node to node, allowing rapid saltatory conduction
[CORRECT]
C. Cerebrospinal fluid is filtered into the axoplasm
D. Myelin sheath segments are actively regenerated
Correct Answer: B
, Rationale: Nodes of Ranvier contain clustered voltage-gated channels that permit
saltatory conduction, greatly increasing speed. Neurotransmitter release occurs only at
synaptic knobs, and myelin is not regenerated at these gaps.
Q4: While viewing a CNS tissue slide, a lab group identifies the most abundant,
star-shaped glial cells whose perivascular "feet" cling to blood capillaries. Which
function is associated with these astrocytes?
A. Helping form and maintain the blood-brain barrier [CORRECT]
B. Myelinating axons of the peripheral nervous system
C. Propagating action potentials between neurons
D. Producing action potentials that trigger muscle contraction
Correct Answer: A
Rationale: Astrocytes' end-feet contribute structurally and chemically to the blood-brain
barrier. Glial cells never conduct action potentials, and Schwann cells—not
astrocytes—myelinate PNS fibers.
Q5: On the laboratory synapse model, the bulbous distal endings of the axon terminal
are shown containing numerous membrane-bound vesicles. What event occurs at these
synaptic knobs when an action potential arrives?
A. Synaptic vesicles release neurotransmitter into the synaptic cleft by exocytosis
[CORRECT]
B. The myelin sheath wraps around the postsynaptic membrane
C. Sodium-potassium pumps establish the resting membrane potential of the dendrite
D. The presynaptic neuron divides into two daughter cells
Correct Answer: A
Rationale: Calcium influx at the synaptic knob triggers vesicular exocytosis of
neurotransmitter across the cleft. Myelination, resting potential maintenance, and cell
division do not occur at this site.
Q6: A slide of brain tissue from a patient with viral encephalitis shows small, ovoid glial
cells that have enlarged and become actively phagocytic, engulfing pathogens and
cellular debris. Which neuroglial cell is performing this function?
A. Astrocyte
B. Microglia [CORRECT]
C. Ependymal cell
D. Satellite cell
Correct Answer: B
Rationale: Microglia act as the resident macrophages of the CNS, activating during
infection or injury. Astrocytes support the BBB, ependymal cells line ventricles, and
satellite cells support PNS ganglia.
– Complete 30 Questions with Detailed Rationales | 100% Verified | Pass Guaranteed –
A+ Graded
SECTION A: NERVOUS TISSUE & NEURON ANATOMY (Q1–Q6)
Q1: During the lab practical, a pointer on the neuron model indicates the single, long
cytoplasmic extension that conducts nerve impulses away from the cell body toward an
effector. Which structure is being identified?
A. Dendrite
B. Axon hillock
C. Axon [CORRECT]
D. Chromatophilic (Nissl) substance
Correct Answer: C
Rationale: The axon transmits impulses away from the soma, whereas dendrites
conduct impulses toward it. The axon hillock is only the cone-shaped origin region, and
Nissl substance is rough ER found within the cell body.
Q2: Which type of neuroglial cell forms the myelin sheath around axons within the
central nervous system (CNS)?
A. Schwann cell
B. Satellite cell
C. Microglia
D. Oligodendrocyte [CORRECT]
Correct Answer: D
Rationale: Oligodendrocytes myelinate CNS axons, with each cell wrapping segments of
multiple fibers. Schwann cells myelinate in the PNS, satellite cells support ganglion cell
bodies, and microglia are phagocytes.
Q3: A student examines a longitudinal microscope slide of a myelinated peripheral
nerve fiber and observes small uninsulated gaps between adjacent Schwann cells along
the axon. What physiologically occurs at these nodes of Ranvier?
A. Neurotransmitter is released into the synaptic cleft
B. Action potentials "jump" from node to node, allowing rapid saltatory conduction
[CORRECT]
C. Cerebrospinal fluid is filtered into the axoplasm
D. Myelin sheath segments are actively regenerated
Correct Answer: B
, Rationale: Nodes of Ranvier contain clustered voltage-gated channels that permit
saltatory conduction, greatly increasing speed. Neurotransmitter release occurs only at
synaptic knobs, and myelin is not regenerated at these gaps.
Q4: While viewing a CNS tissue slide, a lab group identifies the most abundant,
star-shaped glial cells whose perivascular "feet" cling to blood capillaries. Which
function is associated with these astrocytes?
A. Helping form and maintain the blood-brain barrier [CORRECT]
B. Myelinating axons of the peripheral nervous system
C. Propagating action potentials between neurons
D. Producing action potentials that trigger muscle contraction
Correct Answer: A
Rationale: Astrocytes' end-feet contribute structurally and chemically to the blood-brain
barrier. Glial cells never conduct action potentials, and Schwann cells—not
astrocytes—myelinate PNS fibers.
Q5: On the laboratory synapse model, the bulbous distal endings of the axon terminal
are shown containing numerous membrane-bound vesicles. What event occurs at these
synaptic knobs when an action potential arrives?
A. Synaptic vesicles release neurotransmitter into the synaptic cleft by exocytosis
[CORRECT]
B. The myelin sheath wraps around the postsynaptic membrane
C. Sodium-potassium pumps establish the resting membrane potential of the dendrite
D. The presynaptic neuron divides into two daughter cells
Correct Answer: A
Rationale: Calcium influx at the synaptic knob triggers vesicular exocytosis of
neurotransmitter across the cleft. Myelination, resting potential maintenance, and cell
division do not occur at this site.
Q6: A slide of brain tissue from a patient with viral encephalitis shows small, ovoid glial
cells that have enlarged and become actively phagocytic, engulfing pathogens and
cellular debris. Which neuroglial cell is performing this function?
A. Astrocyte
B. Microglia [CORRECT]
C. Ependymal cell
D. Satellite cell
Correct Answer: B
Rationale: Microglia act as the resident macrophages of the CNS, activating during
infection or injury. Astrocytes support the BBB, ependymal cells line ventricles, and
satellite cells support PNS ganglia.
