,Q1 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
A researcher treats cultured epithelial cells with a drug that inhibits the Na+/K+
ATPase. Which of the following immediate cellular consequences is most likely?
A. Increased intracellular Na+ concentration and cell swelling due to osmotic water influx.
CORRECT
B. Hyperpolarization of the plasma membrane due to reduced Na+ efflux.
C. Increased activity of the Na+/Ca2+ exchanger to compensate for the Na+ gradient loss.
D. Stimulation of endocytosis to internalize excess membrane proteins.
RATIONALE: The Na+/K+ ATPase maintains the low intracellular Na+ and high intracellular K+
concentrations. Inhibition leads to Na+ accumulation, which increases intracellular osmolarity,
causing water influx and cell swelling. The membrane potential would depolarize, not
hyperpolarize, and the Na+/Ca2+ exchanger would be impaired, not stimulated, due to the
reduced Na+ gradient.
Q2 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
Which of the following best explains why stratified squamous epithelium is
well-suited for the oral cavity but not for the alveoli?
A. Stratified squamous epithelium is keratinized, preventing gas exchange.
B. Its thick, multi-layered structure provides protection against abrasion but limits diffusion.
CORRECT
C. It contains goblet cells that secrete mucus, which would block air flow.
D. It lacks blood vessels, making it unable to support rapid gas transport.
RATIONALE: Stratified squamous epithelium is multi-layered, providing robust protection against
mechanical stress, ideal for the oral cavity. However, its thickness increases the diffusion
distance, making it unsuitable for the alveoli, where simple squamous epithelium facilitates rapid
gas exchange. The other options are incorrect because stratified squamous epithelium is not
necessarily keratinized, does not typically contain goblet cells, and vascularity is not the primary
limitation.
Page 2
,Q3 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
A patient presents with a severe sunburn that has damaged the superficial layers
of the skin. Which of the following structures would be least likely to be directly
affected?
A. Stratum corneum
B. Dermal papillae CORRECT
C. Stratum basale
D. Melanocytes
RATIONALE: The dermal papillae are located in the papillary layer of the dermis, deep to the
epidermis. A superficial sunburn primarily affects the epidermal layers, including the stratum
corneum, stratum basale, and melanocytes. The dermal papillae are less likely to be directly
affected unless the burn is deeper, involving the dermis.
Q4 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
During intramembranous ossification, which of the following cellular events is
most critical for the formation of trabeculae?
A. Chondrocytes hypertrophy and calcify the surrounding matrix.
B. Osteoblasts deposit osteoid within a highly vascularized mesenchymal membrane.
CORRECT
C. Osteoclasts carve out the medullary cavity in the center of the bone.
D. Perichondrium transforms into periosteum and secretes compact bone.
RATIONALE: Intramembranous ossification involves the direct differentiation of mesenchymal
cells into osteoblasts, which secrete osteoid that mineralizes, forming trabeculae. Chondrocyte
hypertrophy is characteristic of endochondral ossification. Osteoclasts are not involved in the
initial formation of trabeculae, and the transformation of perichondrium is not a feature of
intramembranous ossification.
Page 3
, Q5 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
Which of the following best describes the structural and functional relationship
between the sarcoplasmic reticulum (SR) and T-tubules in skeletal muscle
contraction?
A. T-tubules store Ca2+ and release it upon action potential arrival, while the SR propagates the
signal.
B. The SR releases Ca2+ through voltage-gated channels triggered by the T-tubule action
potential. CORRECT
C. T-tubules are continuous with the SR, allowing direct passage of Ca2+ into the cytosol.
D. The SR generates action potentials that are transmitted to the T-tubules via gap junctions.
RATIONALE: In skeletal muscle, T-tubules are invaginations of the sarcolemma that conduct
action potentials deep into the muscle fiber. The action potential triggers the opening of
dihydropyridine receptors on the T-tubule, which mechanically gate ryanodine receptors on the
SR, causing Ca2+ release. The SR is the Ca2+ store, not the T-tubule, and they are not
continuous or connected by gap junctions.
Q6 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
A drug that blocks voltage-gated sodium channels in a neuron would most likely
have which of the following effects on the action potential?
A. It would prevent repolarization, leaving the membrane depolarized.
B. It would prevent the depolarization phase, so no action potential would be generated.
CORRECT
C. It would shorten the absolute refractory period, allowing higher firing frequencies.
D. It would enhance the hyperpolarization phase, making the neuron more excitable.
RATIONALE: Voltage-gated sodium channels are responsible for the rapid depolarization phase
of the action potential. Blocking them prevents the influx of Na+, so the membrane cannot
depolarize to threshold and no action potential is generated. Repolarization is primarily due to K+
efflux, so it would not be directly prevented. The refractory period and hyperpolarization are not
affected in the manner described.
Page 4
ORGANIZATION OF THE HUMAN BODY
A researcher treats cultured epithelial cells with a drug that inhibits the Na+/K+
ATPase. Which of the following immediate cellular consequences is most likely?
A. Increased intracellular Na+ concentration and cell swelling due to osmotic water influx.
CORRECT
B. Hyperpolarization of the plasma membrane due to reduced Na+ efflux.
C. Increased activity of the Na+/Ca2+ exchanger to compensate for the Na+ gradient loss.
D. Stimulation of endocytosis to internalize excess membrane proteins.
RATIONALE: The Na+/K+ ATPase maintains the low intracellular Na+ and high intracellular K+
concentrations. Inhibition leads to Na+ accumulation, which increases intracellular osmolarity,
causing water influx and cell swelling. The membrane potential would depolarize, not
hyperpolarize, and the Na+/Ca2+ exchanger would be impaired, not stimulated, due to the
reduced Na+ gradient.
Q2 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
Which of the following best explains why stratified squamous epithelium is
well-suited for the oral cavity but not for the alveoli?
A. Stratified squamous epithelium is keratinized, preventing gas exchange.
B. Its thick, multi-layered structure provides protection against abrasion but limits diffusion.
CORRECT
C. It contains goblet cells that secrete mucus, which would block air flow.
D. It lacks blood vessels, making it unable to support rapid gas transport.
RATIONALE: Stratified squamous epithelium is multi-layered, providing robust protection against
mechanical stress, ideal for the oral cavity. However, its thickness increases the diffusion
distance, making it unsuitable for the alveoli, where simple squamous epithelium facilitates rapid
gas exchange. The other options are incorrect because stratified squamous epithelium is not
necessarily keratinized, does not typically contain goblet cells, and vascularity is not the primary
limitation.
Page 2
,Q3 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
A patient presents with a severe sunburn that has damaged the superficial layers
of the skin. Which of the following structures would be least likely to be directly
affected?
A. Stratum corneum
B. Dermal papillae CORRECT
C. Stratum basale
D. Melanocytes
RATIONALE: The dermal papillae are located in the papillary layer of the dermis, deep to the
epidermis. A superficial sunburn primarily affects the epidermal layers, including the stratum
corneum, stratum basale, and melanocytes. The dermal papillae are less likely to be directly
affected unless the burn is deeper, involving the dermis.
Q4 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
During intramembranous ossification, which of the following cellular events is
most critical for the formation of trabeculae?
A. Chondrocytes hypertrophy and calcify the surrounding matrix.
B. Osteoblasts deposit osteoid within a highly vascularized mesenchymal membrane.
CORRECT
C. Osteoclasts carve out the medullary cavity in the center of the bone.
D. Perichondrium transforms into periosteum and secretes compact bone.
RATIONALE: Intramembranous ossification involves the direct differentiation of mesenchymal
cells into osteoblasts, which secrete osteoid that mineralizes, forming trabeculae. Chondrocyte
hypertrophy is characteristic of endochondral ossification. Osteoclasts are not involved in the
initial formation of trabeculae, and the transformation of perichondrium is not a feature of
intramembranous ossification.
Page 3
, Q5 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
Which of the following best describes the structural and functional relationship
between the sarcoplasmic reticulum (SR) and T-tubules in skeletal muscle
contraction?
A. T-tubules store Ca2+ and release it upon action potential arrival, while the SR propagates the
signal.
B. The SR releases Ca2+ through voltage-gated channels triggered by the T-tubule action
potential. CORRECT
C. T-tubules are continuous with the SR, allowing direct passage of Ca2+ into the cytosol.
D. The SR generates action potentials that are transmitted to the T-tubules via gap junctions.
RATIONALE: In skeletal muscle, T-tubules are invaginations of the sarcolemma that conduct
action potentials deep into the muscle fiber. The action potential triggers the opening of
dihydropyridine receptors on the T-tubule, which mechanically gate ryanodine receptors on the
SR, causing Ca2+ release. The SR is the Ca2+ store, not the T-tubule, and they are not
continuous or connected by gap junctions.
Q6 DEMONSTRATE MASTERY OF ANATOMICAL TERMINOLOGY AND THE STRUCTURAL
ORGANIZATION OF THE HUMAN BODY
A drug that blocks voltage-gated sodium channels in a neuron would most likely
have which of the following effects on the action potential?
A. It would prevent repolarization, leaving the membrane depolarized.
B. It would prevent the depolarization phase, so no action potential would be generated.
CORRECT
C. It would shorten the absolute refractory period, allowing higher firing frequencies.
D. It would enhance the hyperpolarization phase, making the neuron more excitable.
RATIONALE: Voltage-gated sodium channels are responsible for the rapid depolarization phase
of the action potential. Blocking them prevents the influx of Na+, so the membrane cannot
depolarize to threshold and no action potential is generated. Repolarization is primarily due to K+
efflux, so it would not be directly prevented. The refractory period and hyperpolarization are not
affected in the manner described.
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