1
A&P 1 101 MODULE 5 EXAM MUSCULAR SYSTEM
2026/2027 | Portage Learning | Rated A+ | 100% Correct |
Pass Guaranteed
SECTION 1: MUSCLE TISSUE TYPES & HISTOLOGY (Questions 1-
12)
Question 1
A histology student examines a tissue sample under the microscope and observes
long, cylindrical, multinucleated fibers with obvious alternating light and dark bands.
The nuclei are located peripherally, just beneath the sarcolemma. Which muscle
tissue type is being observed?
A. Cardiac muscle tissue B. Smooth muscle tissue C. Skeletal muscle tissue D. Visceral
muscle tissue
Correct Answer: C. Skeletal muscle tissue [CORRECT]
Rationale: Skeletal muscle fibers are long, cylindrical, multinucleated (multiple nuclei
per fiber), and display prominent striations due to the organized sarcomere
arrangement. The peripheral location of nuclei is a key distinguishing feature from
cardiac muscle, which has centrally located nuclei and intercalated discs. Students
often confuse cardiac and skeletal muscle because both are striated, but the
multinucleated, peripheral nuclear arrangement is unique to skeletal muscle.
Question 2
During a laboratory practical, a student is shown a tissue sample with branching
fibers, centrally located nuclei, and dark-staining lines that connect adjacent cells
,2
end-to-end. The fibers also show striations. Which structural feature described serves
as the functional syncytium allowing rapid electrical communication between cells?
A. Central nuclei B. Intercalated discs C. Striations D. Gap junctions within the
sarcoplasmic reticulum
Correct Answer: B. Intercalated discs [CORRECT]
Rationale: Intercalated discs are specialized junctions unique to cardiac muscle that
contain desmosomes (for mechanical coupling) and gap junctions (for electrical
coupling), allowing action potentials to spread rapidly from cell to cell, creating a
functional syncytium. While gap junctions are indeed present within intercalated
discs, they are not located in the sarcoplasmic reticulum. The common error is
selecting "gap junctions" without recognizing that in cardiac muscle, these are
specifically housed within the intercalated disc structure.
Question 3
A pathologist receives a biopsy from the wall of a hollow organ. The tissue shows
spindle-shaped cells with a single, centrally located nucleus, no visible striations, and
the cells are arranged in sheets. Which statement about the control of this muscle
type is correct?
A. It is under voluntary control via somatic motor neurons B. It is under involuntary
control via autonomic nervous system and local factors C. It requires motor end
plates and acetylcholine for every contraction D. It contracts only in response to
hormones from the anterior pituitary
Correct Answer: B. It is under involuntary control via autonomic nervous system
and local factors [CORRECT]
Rationale: The description identifies smooth muscle tissue (spindle-shaped,
uninucleated, non-striated), which is found in the walls of hollow organs and is under
involuntary control by the autonomic nervous system, local chemical factors (pH,
oxygen, stretch), and hormones. Skeletal muscle is the only type under voluntary
control. The common misconception is that all muscle requires ACh at a
,3
neuromuscular junction; smooth muscle receives diffuse autonomic innervation and
responds to multiple local and hormonal signals.
Question 4
A medical student is comparing three muscle tissue types. Which of the following
correctly pairs the muscle type with its characteristic nucleation pattern?
A. Skeletal: uninucleated; Cardiac: multinucleated; Smooth: multinucleated B. Skeletal:
multinucleated (peripheral); Cardiac: uninucleated or binucleated (central); Smooth:
uninucleated (central) C. Skeletal: uninucleated (central); Cardiac: multinucleated
(peripheral); Smooth: multinucleated (central) D. Skeletal: binucleated (peripheral);
Cardiac: multinucleated (central); Smooth: anucleated
Correct Answer: B. Skeletal: multinucleated (peripheral); Cardiac: uninucleated
or binucleated (central); Smooth: uninucleated (central) [CORRECT]
Rationale: This is a fundamental histological distinction. Skeletal muscle fibers are
formed by fusion of myoblasts, resulting in multinucleated fibers with peripheral
nuclei. Cardiac muscle cells typically have one or two centrally located nuclei. Smooth
muscle cells are spindle-shaped with a single central nucleus. A common student
error is reversing the nuclear locations of skeletal and cardiac muscle or assuming
cardiac muscle is multinucleated like skeletal muscle.
Question 5
A histology instructor asks students to identify which muscle tissue type contains T-
tubules located at the Z-discs rather than at the A-I band junction. Which tissue is
being described?
A. Skeletal muscle tissue B. Cardiac muscle tissue C. Smooth muscle tissue D. Both
skeletal and cardiac muscle tissue
Correct Answer: B. Cardiac muscle tissue [CORRECT]
, 4
Rationale: Cardiac muscle T-tubules are located at the Z-discs and are wider than
skeletal muscle T-tubules, which are located at the A-I band junction (M-line region
in some species). This structural difference is important for excitation-contraction
coupling. Smooth muscle lacks organized T-tubules entirely. Students frequently
confuse T-tubule locations between muscle types or assume all striated muscle has
identical T-tubule anatomy.
Question 6
During a microscopy lab, a student observes a tissue sample where individual cells
are separated by connective tissue and show no branching. The cells are very long
and show cross-striations. Which additional feature would confirm this is skeletal
muscle rather than cardiac muscle?
A. Presence of intercalated discs with gap junctions B. Presence of branching fibers
with centrally located nuclei C. Presence of multiple peripheral nuclei and no
intercalated discs D. Presence of a single central nucleus and lipofuscin granules
Correct Answer: C. Presence of multiple peripheral nuclei and no intercalated
discs [CORRECT]
Rationale: The absence of intercalated discs rules out cardiac muscle, and the
presence of multiple peripheral nuclei definitively identifies skeletal muscle. Cardiac
muscle has intercalated discs, branching fibers, and typically one or two central
nuclei. Lipofuscin granules are "wear-and-tear" pigments found in aging cardiac
muscle cells but are not diagnostic. Students often mistakenly look for striations
alone, but both skeletal and cardiac muscle are striated.
Question 7
A patient presents with difficulty swallowing. The physician suspects a problem with
the muscularis layer of the esophagus. Which histological characteristics would be
expected in a biopsy of this muscle layer?
A&P 1 101 MODULE 5 EXAM MUSCULAR SYSTEM
2026/2027 | Portage Learning | Rated A+ | 100% Correct |
Pass Guaranteed
SECTION 1: MUSCLE TISSUE TYPES & HISTOLOGY (Questions 1-
12)
Question 1
A histology student examines a tissue sample under the microscope and observes
long, cylindrical, multinucleated fibers with obvious alternating light and dark bands.
The nuclei are located peripherally, just beneath the sarcolemma. Which muscle
tissue type is being observed?
A. Cardiac muscle tissue B. Smooth muscle tissue C. Skeletal muscle tissue D. Visceral
muscle tissue
Correct Answer: C. Skeletal muscle tissue [CORRECT]
Rationale: Skeletal muscle fibers are long, cylindrical, multinucleated (multiple nuclei
per fiber), and display prominent striations due to the organized sarcomere
arrangement. The peripheral location of nuclei is a key distinguishing feature from
cardiac muscle, which has centrally located nuclei and intercalated discs. Students
often confuse cardiac and skeletal muscle because both are striated, but the
multinucleated, peripheral nuclear arrangement is unique to skeletal muscle.
Question 2
During a laboratory practical, a student is shown a tissue sample with branching
fibers, centrally located nuclei, and dark-staining lines that connect adjacent cells
,2
end-to-end. The fibers also show striations. Which structural feature described serves
as the functional syncytium allowing rapid electrical communication between cells?
A. Central nuclei B. Intercalated discs C. Striations D. Gap junctions within the
sarcoplasmic reticulum
Correct Answer: B. Intercalated discs [CORRECT]
Rationale: Intercalated discs are specialized junctions unique to cardiac muscle that
contain desmosomes (for mechanical coupling) and gap junctions (for electrical
coupling), allowing action potentials to spread rapidly from cell to cell, creating a
functional syncytium. While gap junctions are indeed present within intercalated
discs, they are not located in the sarcoplasmic reticulum. The common error is
selecting "gap junctions" without recognizing that in cardiac muscle, these are
specifically housed within the intercalated disc structure.
Question 3
A pathologist receives a biopsy from the wall of a hollow organ. The tissue shows
spindle-shaped cells with a single, centrally located nucleus, no visible striations, and
the cells are arranged in sheets. Which statement about the control of this muscle
type is correct?
A. It is under voluntary control via somatic motor neurons B. It is under involuntary
control via autonomic nervous system and local factors C. It requires motor end
plates and acetylcholine for every contraction D. It contracts only in response to
hormones from the anterior pituitary
Correct Answer: B. It is under involuntary control via autonomic nervous system
and local factors [CORRECT]
Rationale: The description identifies smooth muscle tissue (spindle-shaped,
uninucleated, non-striated), which is found in the walls of hollow organs and is under
involuntary control by the autonomic nervous system, local chemical factors (pH,
oxygen, stretch), and hormones. Skeletal muscle is the only type under voluntary
control. The common misconception is that all muscle requires ACh at a
,3
neuromuscular junction; smooth muscle receives diffuse autonomic innervation and
responds to multiple local and hormonal signals.
Question 4
A medical student is comparing three muscle tissue types. Which of the following
correctly pairs the muscle type with its characteristic nucleation pattern?
A. Skeletal: uninucleated; Cardiac: multinucleated; Smooth: multinucleated B. Skeletal:
multinucleated (peripheral); Cardiac: uninucleated or binucleated (central); Smooth:
uninucleated (central) C. Skeletal: uninucleated (central); Cardiac: multinucleated
(peripheral); Smooth: multinucleated (central) D. Skeletal: binucleated (peripheral);
Cardiac: multinucleated (central); Smooth: anucleated
Correct Answer: B. Skeletal: multinucleated (peripheral); Cardiac: uninucleated
or binucleated (central); Smooth: uninucleated (central) [CORRECT]
Rationale: This is a fundamental histological distinction. Skeletal muscle fibers are
formed by fusion of myoblasts, resulting in multinucleated fibers with peripheral
nuclei. Cardiac muscle cells typically have one or two centrally located nuclei. Smooth
muscle cells are spindle-shaped with a single central nucleus. A common student
error is reversing the nuclear locations of skeletal and cardiac muscle or assuming
cardiac muscle is multinucleated like skeletal muscle.
Question 5
A histology instructor asks students to identify which muscle tissue type contains T-
tubules located at the Z-discs rather than at the A-I band junction. Which tissue is
being described?
A. Skeletal muscle tissue B. Cardiac muscle tissue C. Smooth muscle tissue D. Both
skeletal and cardiac muscle tissue
Correct Answer: B. Cardiac muscle tissue [CORRECT]
, 4
Rationale: Cardiac muscle T-tubules are located at the Z-discs and are wider than
skeletal muscle T-tubules, which are located at the A-I band junction (M-line region
in some species). This structural difference is important for excitation-contraction
coupling. Smooth muscle lacks organized T-tubules entirely. Students frequently
confuse T-tubule locations between muscle types or assume all striated muscle has
identical T-tubule anatomy.
Question 6
During a microscopy lab, a student observes a tissue sample where individual cells
are separated by connective tissue and show no branching. The cells are very long
and show cross-striations. Which additional feature would confirm this is skeletal
muscle rather than cardiac muscle?
A. Presence of intercalated discs with gap junctions B. Presence of branching fibers
with centrally located nuclei C. Presence of multiple peripheral nuclei and no
intercalated discs D. Presence of a single central nucleus and lipofuscin granules
Correct Answer: C. Presence of multiple peripheral nuclei and no intercalated
discs [CORRECT]
Rationale: The absence of intercalated discs rules out cardiac muscle, and the
presence of multiple peripheral nuclei definitively identifies skeletal muscle. Cardiac
muscle has intercalated discs, branching fibers, and typically one or two central
nuclei. Lipofuscin granules are "wear-and-tear" pigments found in aging cardiac
muscle cells but are not diagnostic. Students often mistakenly look for striations
alone, but both skeletal and cardiac muscle are striated.
Question 7
A patient presents with difficulty swallowing. The physician suspects a problem with
the muscularis layer of the esophagus. Which histological characteristics would be
expected in a biopsy of this muscle layer?
