COMSAE PHASE 1 HISTOLOGY PRACTICE
EXAM WITH ACTUAL QUESTIONS AND
VERIFIED ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
Question 1
A tissue specimen demonstrates closely packed cells with very little
extracellular matrix. The cells exhibit distinct apical, lateral, and basal
surfaces. The apical surface faces a lumen, while the basal surface rests
on a thin extracellular layer separating the cells from underlying
connective tissue. Which feature best identifies this tissue as epithelium?
A. Abundant type I collagen bundles
B. Presence of a basement membrane and cellular polarity
C. Extensive extracellular matrix with scattered fibroblasts
D. Numerous intercellular gap junctions without a free surface
Answer: B. Presence of a basement membrane and cellular polarity
Rationale: Epithelial tissue is characterized by tightly packed cells,
minimal extracellular matrix, cellular polarity, and attachment to a
basement membrane. The basement membrane separates epithelium
from underlying connective tissue and consists primarily of basal
lamina and reticular lamina. Type I collagen bundles are
characteristic of dense connective tissue, while gap junctions can
occur in many tissues and are not diagnostic of epithelium.
Question 2
A histologic section of the trachea demonstrates a respiratory epithelium
containing ciliated cells, goblet cells, basal cells, and nuclei located at
1
,different levels. All cells contact the basement membrane, but not all
reach the luminal surface. Which classification is most appropriate?
A. Simple cuboidal epithelium
B. Stratified squamous epithelium
C. Pseudostratified ciliated columnar epithelium
D. Transitional epithelium
Answer: C. Pseudostratified ciliated columnar epithelium
Rationale: Pseudostratified epithelium appears multilayered because
nuclei lie at different levels, but every cell contacts the basement
membrane. In the respiratory tract, it is typically ciliated and contains
mucus-producing goblet cells. Simple cuboidal epithelium has a single
layer of cuboidal cells, stratified squamous epithelium has multiple
layers with squamous superficial cells, and transitional epithelium is
specialized for urinary tract distension.
Question 3
A renal biopsy demonstrates a single layer of cube-shaped cells
surrounding numerous small tubules. The cells have centrally located
round nuclei and relatively little cytoplasm. Which epithelial type is
most likely present?
A. Simple cuboidal epithelium
B. Simple squamous epithelium
C. Stratified cuboidal epithelium
D. Pseudostratified columnar epithelium
Answer: A. Simple cuboidal epithelium
Rationale: Simple cuboidal epithelium consists of one layer of cells
approximately as tall as they are wide, usually with centrally located
spherical nuclei. It is common in renal tubules and thyroid follicles
and is involved in secretion and absorption. Simple squamous
2
,epithelium is thinner and specialized for diffusion, whereas stratified
cuboidal epithelium contains multiple cellular layers.
Question 4
A histologic section from the alveolar region of the lung shows
extremely thin cells lining the air spaces. Their flattened nuclei bulge
slightly into the lumen. Which epithelial cell type is primarily
responsible for the thin diffusion barrier between alveolar air and
pulmonary capillary blood?
A. Type II pneumocytes
B. Club cells
C. Type I pneumocytes
D. Alveolar macrophages
Answer: C. Type I pneumocytes
Rationale: Type I pneumocytes are extremely thin simple squamous
cells covering most of the alveolar surface and forming a major
component of the blood-air barrier. Type II pneumocytes are cuboidal
cells that synthesize pulmonary surfactant and can proliferate after
injury. Alveolar macrophages are immune cells located within alveoli
and interstitium.
Question 5
A biopsy of the urinary bladder reveals a multilayered epithelium whose
superficial cells are large and dome-shaped when the bladder is relaxed.
With distension, these cells become flatter. Which epithelial
specialization is demonstrated?
A. Keratinized stratified squamous epithelium
B. Pseudostratified columnar epithelium
3
, C. Transitional epithelium
D. Simple columnar epithelium
Answer: C. Transitional epithelium
Rationale: Transitional epithelium, or urothelium, lines much of the
urinary tract and is specialized to accommodate substantial changes in
organ volume. Its superficial umbrella cells change shape during
distension. The epithelium also forms a highly effective permeability
barrier against urine.
Question 6
A patient has impaired mucociliary clearance because of an inherited
defect affecting the ultrastructure of motile cilia. Which structural
component is most directly involved?
A. Nine peripheral microtubule doublets surrounding two central
microtubules
B. Nine peripheral microtubule triplets without central microtubules
C. Bundles of intermediate filaments attached to desmosomes
D. Actin filaments attached to dense bodies
Answer: A. Nine peripheral microtubule doublets surrounding two
central microtubules
Rationale: Motile cilia typically possess a 9+2 axonemal arrangement:
nine peripheral microtubule doublets surrounding two central
microtubules. Dynein arms generate movement using ATP. Primary
cilia generally have a 9+0 arrangement and are usually nonmotile.
Microtubule triplets characterize centrioles and basal bodies rather
than the ciliary axoneme itself.
Question 7
4
EXAM WITH ACTUAL QUESTIONS AND
VERIFIED ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
Question 1
A tissue specimen demonstrates closely packed cells with very little
extracellular matrix. The cells exhibit distinct apical, lateral, and basal
surfaces. The apical surface faces a lumen, while the basal surface rests
on a thin extracellular layer separating the cells from underlying
connective tissue. Which feature best identifies this tissue as epithelium?
A. Abundant type I collagen bundles
B. Presence of a basement membrane and cellular polarity
C. Extensive extracellular matrix with scattered fibroblasts
D. Numerous intercellular gap junctions without a free surface
Answer: B. Presence of a basement membrane and cellular polarity
Rationale: Epithelial tissue is characterized by tightly packed cells,
minimal extracellular matrix, cellular polarity, and attachment to a
basement membrane. The basement membrane separates epithelium
from underlying connective tissue and consists primarily of basal
lamina and reticular lamina. Type I collagen bundles are
characteristic of dense connective tissue, while gap junctions can
occur in many tissues and are not diagnostic of epithelium.
Question 2
A histologic section of the trachea demonstrates a respiratory epithelium
containing ciliated cells, goblet cells, basal cells, and nuclei located at
1
,different levels. All cells contact the basement membrane, but not all
reach the luminal surface. Which classification is most appropriate?
A. Simple cuboidal epithelium
B. Stratified squamous epithelium
C. Pseudostratified ciliated columnar epithelium
D. Transitional epithelium
Answer: C. Pseudostratified ciliated columnar epithelium
Rationale: Pseudostratified epithelium appears multilayered because
nuclei lie at different levels, but every cell contacts the basement
membrane. In the respiratory tract, it is typically ciliated and contains
mucus-producing goblet cells. Simple cuboidal epithelium has a single
layer of cuboidal cells, stratified squamous epithelium has multiple
layers with squamous superficial cells, and transitional epithelium is
specialized for urinary tract distension.
Question 3
A renal biopsy demonstrates a single layer of cube-shaped cells
surrounding numerous small tubules. The cells have centrally located
round nuclei and relatively little cytoplasm. Which epithelial type is
most likely present?
A. Simple cuboidal epithelium
B. Simple squamous epithelium
C. Stratified cuboidal epithelium
D. Pseudostratified columnar epithelium
Answer: A. Simple cuboidal epithelium
Rationale: Simple cuboidal epithelium consists of one layer of cells
approximately as tall as they are wide, usually with centrally located
spherical nuclei. It is common in renal tubules and thyroid follicles
and is involved in secretion and absorption. Simple squamous
2
,epithelium is thinner and specialized for diffusion, whereas stratified
cuboidal epithelium contains multiple cellular layers.
Question 4
A histologic section from the alveolar region of the lung shows
extremely thin cells lining the air spaces. Their flattened nuclei bulge
slightly into the lumen. Which epithelial cell type is primarily
responsible for the thin diffusion barrier between alveolar air and
pulmonary capillary blood?
A. Type II pneumocytes
B. Club cells
C. Type I pneumocytes
D. Alveolar macrophages
Answer: C. Type I pneumocytes
Rationale: Type I pneumocytes are extremely thin simple squamous
cells covering most of the alveolar surface and forming a major
component of the blood-air barrier. Type II pneumocytes are cuboidal
cells that synthesize pulmonary surfactant and can proliferate after
injury. Alveolar macrophages are immune cells located within alveoli
and interstitium.
Question 5
A biopsy of the urinary bladder reveals a multilayered epithelium whose
superficial cells are large and dome-shaped when the bladder is relaxed.
With distension, these cells become flatter. Which epithelial
specialization is demonstrated?
A. Keratinized stratified squamous epithelium
B. Pseudostratified columnar epithelium
3
, C. Transitional epithelium
D. Simple columnar epithelium
Answer: C. Transitional epithelium
Rationale: Transitional epithelium, or urothelium, lines much of the
urinary tract and is specialized to accommodate substantial changes in
organ volume. Its superficial umbrella cells change shape during
distension. The epithelium also forms a highly effective permeability
barrier against urine.
Question 6
A patient has impaired mucociliary clearance because of an inherited
defect affecting the ultrastructure of motile cilia. Which structural
component is most directly involved?
A. Nine peripheral microtubule doublets surrounding two central
microtubules
B. Nine peripheral microtubule triplets without central microtubules
C. Bundles of intermediate filaments attached to desmosomes
D. Actin filaments attached to dense bodies
Answer: A. Nine peripheral microtubule doublets surrounding two
central microtubules
Rationale: Motile cilia typically possess a 9+2 axonemal arrangement:
nine peripheral microtubule doublets surrounding two central
microtubules. Dynein arms generate movement using ATP. Primary
cilia generally have a 9+0 arrangement and are usually nonmotile.
Microtubule triplets characterize centrioles and basal bodies rather
than the ciliary axoneme itself.
Question 7
4
