WGU D312 Anatomy and Physiology I
Objective Assessment Exam
2026/2027 Newly Released
70 Verified Questions with answers and expert rationales
Q1: A patient presents with loss of sensation over the lateral aspect of the forearm and thumb,
along with weakness in wrist extension. Which nerve is most likely damaged?
A. Median nerve
B. Radial nerve [CORRECT]
C. Ulnar nerve
D. Musculocutaneous nerve
Correct Answer: B
Rationale: Correct because the radial nerve innervates the posterior compartment of the arm
and forearm, providing sensation to the lateral forearm and dorsal hand (thumb side) and
motor innervation to wrist and finger extensors. Damage to this nerve produces wrist drop and
sensory loss over the lateral forearm, matching the clinical presentation described.
Q2: During mitosis, which event occurs during anaphase?
A. Chromosomes align at the metaphase plate
B. Sister chromatids separate and move toward opposite poles [CORRECT]
C. Nuclear envelope breaks down
D. Chromosomes decondense and nuclear envelope reforms
Correct Answer: B
Rationale: Correct because during anaphase, the cohesin proteins holding sister chromatids
together are cleaved, allowing the separated chromatids (now individual chromosomes) to be
pulled toward opposite poles of the cell by shortening kinetochore microtubules. Chromosome
,alignment occurs in metaphase, nuclear envelope breakdown in prophase, and decondensation
in telophase.
Q3: A histology slide shows a tissue with multiple layers of cells, where the surface cells are flat
and scale-like. This tissue is best classified as:
A. Stratified squamous epithelium [CORRECT]
B. Pseudostratified columnar epithelium
C. Simple squamous epithelium
D. Transitional epithelium
Correct Answer: A
Rationale: Correct because stratified squamous epithelium is characterized by multiple cell
layers with the apical (surface) cells being flat (squamous) in shape, providing protection against
abrasion. This tissue is found in areas subject to mechanical stress such as the epidermis, oral
cavity, and esophagus. Simple squamous has only one layer, pseudostratified appears layered
but all cells contact the basement membrane, and transitional epithelium changes shape with
stretching.
Q4: Which type of muscle fiber is best suited for maintaining posture over extended periods?
A. Type IIb fibers
B. Type I fibers [CORRECT]
C. Type IIa fibers
D. Type IIx fibers
Correct Answer: B
Rationale: Correct because Type I (slow oxidative) muscle fibers are rich in mitochondria,
myoglobin, and capillaries, giving them a red appearance and high fatigue resistance ideal for
sustained, low-intensity activities like postural maintenance. Type IIb/IIx fibers are fast glycolytic
and fatigue rapidly, while Type IIa are intermediate fast oxidative-glycolytic fibers suited for
moderate-duration activities.
, Q5: A 45-year-old patient suffers a deep partial-thickness burn affecting the epidermis and
upper dermis. Which clinical finding is most expected?
A. Charred, painless skin requiring grafting
B. Blistering with severe pain [CORRECT]
C. Redness and pain without blistering
D. White, leathery skin with no sensation
Correct Answer: B
Rationale: Correct because second-degree (partial-thickness) burns destroy the epidermis and
extend into the dermis, damaging nerve endings enough to cause severe pain while also
damaging the dermal-epidermal junction, leading to fluid accumulation and blister formation.
First-degree burns cause redness and pain without blistering; third-degree burns are full-
thickness, painless, and require grafting; fourth-degree extends to muscle and bone.
Q6: Which organelle is primarily responsible for ATP production through oxidative
phosphorylation?
A. Smooth endoplasmic reticulum
B. Mitochondria [CORRECT]
C. Golgi apparatus
D. Lysosome
Correct Answer: B
Rationale: Correct because mitochondria are the primary site of aerobic cellular respiration,
where the electron transport chain and ATP synthase on the inner mitochondrial membrane
(cristae) generate the majority of cellular ATP through oxidative phosphorylation. The smooth
ER synthesizes lipids and detoxifies, the Golgi packages and sorts proteins, and lysosomes
perform intracellular digestion.
Objective Assessment Exam
2026/2027 Newly Released
70 Verified Questions with answers and expert rationales
Q1: A patient presents with loss of sensation over the lateral aspect of the forearm and thumb,
along with weakness in wrist extension. Which nerve is most likely damaged?
A. Median nerve
B. Radial nerve [CORRECT]
C. Ulnar nerve
D. Musculocutaneous nerve
Correct Answer: B
Rationale: Correct because the radial nerve innervates the posterior compartment of the arm
and forearm, providing sensation to the lateral forearm and dorsal hand (thumb side) and
motor innervation to wrist and finger extensors. Damage to this nerve produces wrist drop and
sensory loss over the lateral forearm, matching the clinical presentation described.
Q2: During mitosis, which event occurs during anaphase?
A. Chromosomes align at the metaphase plate
B. Sister chromatids separate and move toward opposite poles [CORRECT]
C. Nuclear envelope breaks down
D. Chromosomes decondense and nuclear envelope reforms
Correct Answer: B
Rationale: Correct because during anaphase, the cohesin proteins holding sister chromatids
together are cleaved, allowing the separated chromatids (now individual chromosomes) to be
pulled toward opposite poles of the cell by shortening kinetochore microtubules. Chromosome
,alignment occurs in metaphase, nuclear envelope breakdown in prophase, and decondensation
in telophase.
Q3: A histology slide shows a tissue with multiple layers of cells, where the surface cells are flat
and scale-like. This tissue is best classified as:
A. Stratified squamous epithelium [CORRECT]
B. Pseudostratified columnar epithelium
C. Simple squamous epithelium
D. Transitional epithelium
Correct Answer: A
Rationale: Correct because stratified squamous epithelium is characterized by multiple cell
layers with the apical (surface) cells being flat (squamous) in shape, providing protection against
abrasion. This tissue is found in areas subject to mechanical stress such as the epidermis, oral
cavity, and esophagus. Simple squamous has only one layer, pseudostratified appears layered
but all cells contact the basement membrane, and transitional epithelium changes shape with
stretching.
Q4: Which type of muscle fiber is best suited for maintaining posture over extended periods?
A. Type IIb fibers
B. Type I fibers [CORRECT]
C. Type IIa fibers
D. Type IIx fibers
Correct Answer: B
Rationale: Correct because Type I (slow oxidative) muscle fibers are rich in mitochondria,
myoglobin, and capillaries, giving them a red appearance and high fatigue resistance ideal for
sustained, low-intensity activities like postural maintenance. Type IIb/IIx fibers are fast glycolytic
and fatigue rapidly, while Type IIa are intermediate fast oxidative-glycolytic fibers suited for
moderate-duration activities.
, Q5: A 45-year-old patient suffers a deep partial-thickness burn affecting the epidermis and
upper dermis. Which clinical finding is most expected?
A. Charred, painless skin requiring grafting
B. Blistering with severe pain [CORRECT]
C. Redness and pain without blistering
D. White, leathery skin with no sensation
Correct Answer: B
Rationale: Correct because second-degree (partial-thickness) burns destroy the epidermis and
extend into the dermis, damaging nerve endings enough to cause severe pain while also
damaging the dermal-epidermal junction, leading to fluid accumulation and blister formation.
First-degree burns cause redness and pain without blistering; third-degree burns are full-
thickness, painless, and require grafting; fourth-degree extends to muscle and bone.
Q6: Which organelle is primarily responsible for ATP production through oxidative
phosphorylation?
A. Smooth endoplasmic reticulum
B. Mitochondria [CORRECT]
C. Golgi apparatus
D. Lysosome
Correct Answer: B
Rationale: Correct because mitochondria are the primary site of aerobic cellular respiration,
where the electron transport chain and ATP synthase on the inner mitochondrial membrane
(cristae) generate the majority of cellular ATP through oxidative phosphorylation. The smooth
ER synthesizes lipids and detoxifies, the Golgi packages and sorts proteins, and lysosomes
perform intracellular digestion.
