BIO 151 Lab 4 Exam Muscle & Nervous Tissue Histology
Actual Exam 2026/2027 – Complete Portage Learning
Questions with Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
SECTION A: MUSCLE TISSUE IDENTIFICATION & HISTOLOGY (Q1–Q6)
Q1: A microscope slide from the lab 4 slide box shows long, unbranched, cylindrical
cells with clearly visible cross-striations and multiple nuclei located at the periphery of
each cell. Which tissue is on this slide?
A. Smooth muscle
B. Skeletal muscle [CORRECT]
C. Cardiac muscle
D. Nervous tissue
Correct Answer: B
Rationale: Long, unbranched, striated fibers with multiple peripherally located nuclei are
the identifying features of skeletal muscle; cardiac muscle is branching with
intercalated discs, and smooth muscle lacks both striations and peripheral nuclei.
Q2: A slide of heart wall tissue shows branching, striated cells joined end-to-end by
dark-staining lines, with one central nucleus per cell. Which tissue and what are the
dark-staining lines?
A. Skeletal muscle; striations
B. Smooth muscle; gap junctions
C. Cardiac muscle; intercalated discs [CORRECT]
D. Nervous tissue; myelin sheaths
Correct Answer: C
Rationale: Branching, striated, uninucleated cells joined by intercalated discs identify
cardiac muscle; skeletal muscle cells do not branch, and smooth muscle has no
striations or intercalated discs.
Q3: A slide taken from the wall of the stomach shows spindle-shaped cells, each with a
single central nucleus and no visible striations. Which tissue is this?
A. Smooth muscle [CORRECT]
B. Skeletal muscle
, C. Cardiac muscle
D. Areolar connective tissue
Correct Answer: A
Rationale: Spindle (fusiform) shape, single central nucleus, and absence of striations
are the classic features of smooth muscle; skeletal and cardiac muscle are both
striated and would not be found in the stomach wall.
Q4: A student asks why intercalated discs are functionally important in cardiac muscle.
What is the BEST answer?
A. They anchor cardiac muscle fibers to the heart's valves
B. They store the calcium released during contraction
C. They insulate heart cells so each contracts independently
D. They contain gap junctions that allow ion flow so the heart muscle contracts as a
synchronized unit [CORRECT]
Correct Answer: D
Rationale: Gap junctions within intercalated discs electrically couple cardiac cells,
enabling rapid, coordinated contraction of the whole heart; intercalated discs do not
anchor to bone, store calcium, or isolate cells from one another.
Q5: Which type of muscle tissue is under voluntary control?
A. Skeletal muscle [CORRECT]
B. Cardiac muscle
C. Smooth muscle
D. All three muscle types equally
Correct Answer: A
Rationale: Skeletal muscle attaches to bone and is consciously controlled; cardiac and
smooth muscle are involuntary and regulated by the autonomic nervous system and
internal pacemakers.
Q6: A student labels a slide from the esophagus wall as "skeletal muscle because the
cells are long." Which observation would CORRECT this error?
A. The cells are multinucleated with peripheral nuclei
B. The cells are spindle-shaped with single central nuclei and lack striations, identifying
smooth muscle [CORRECT]
C. The cells branch and contain intercalated discs
D. The cells contain Nissl bodies and long axons
Correct Answer: B
Rationale: The esophagus wall contains smooth muscle — spindle-shaped, uninucleate,
and non-striated; multinucleation indicates skeletal muscle, branching with discs
indicates cardiac muscle, and Nissl bodies indicate neurons.
Actual Exam 2026/2027 – Complete Portage Learning
Questions with Detailed Rationales | 100% Verified | Pass
Guaranteed – A+ Graded
SECTION A: MUSCLE TISSUE IDENTIFICATION & HISTOLOGY (Q1–Q6)
Q1: A microscope slide from the lab 4 slide box shows long, unbranched, cylindrical
cells with clearly visible cross-striations and multiple nuclei located at the periphery of
each cell. Which tissue is on this slide?
A. Smooth muscle
B. Skeletal muscle [CORRECT]
C. Cardiac muscle
D. Nervous tissue
Correct Answer: B
Rationale: Long, unbranched, striated fibers with multiple peripherally located nuclei are
the identifying features of skeletal muscle; cardiac muscle is branching with
intercalated discs, and smooth muscle lacks both striations and peripheral nuclei.
Q2: A slide of heart wall tissue shows branching, striated cells joined end-to-end by
dark-staining lines, with one central nucleus per cell. Which tissue and what are the
dark-staining lines?
A. Skeletal muscle; striations
B. Smooth muscle; gap junctions
C. Cardiac muscle; intercalated discs [CORRECT]
D. Nervous tissue; myelin sheaths
Correct Answer: C
Rationale: Branching, striated, uninucleated cells joined by intercalated discs identify
cardiac muscle; skeletal muscle cells do not branch, and smooth muscle has no
striations or intercalated discs.
Q3: A slide taken from the wall of the stomach shows spindle-shaped cells, each with a
single central nucleus and no visible striations. Which tissue is this?
A. Smooth muscle [CORRECT]
B. Skeletal muscle
, C. Cardiac muscle
D. Areolar connective tissue
Correct Answer: A
Rationale: Spindle (fusiform) shape, single central nucleus, and absence of striations
are the classic features of smooth muscle; skeletal and cardiac muscle are both
striated and would not be found in the stomach wall.
Q4: A student asks why intercalated discs are functionally important in cardiac muscle.
What is the BEST answer?
A. They anchor cardiac muscle fibers to the heart's valves
B. They store the calcium released during contraction
C. They insulate heart cells so each contracts independently
D. They contain gap junctions that allow ion flow so the heart muscle contracts as a
synchronized unit [CORRECT]
Correct Answer: D
Rationale: Gap junctions within intercalated discs electrically couple cardiac cells,
enabling rapid, coordinated contraction of the whole heart; intercalated discs do not
anchor to bone, store calcium, or isolate cells from one another.
Q5: Which type of muscle tissue is under voluntary control?
A. Skeletal muscle [CORRECT]
B. Cardiac muscle
C. Smooth muscle
D. All three muscle types equally
Correct Answer: A
Rationale: Skeletal muscle attaches to bone and is consciously controlled; cardiac and
smooth muscle are involuntary and regulated by the autonomic nervous system and
internal pacemakers.
Q6: A student labels a slide from the esophagus wall as "skeletal muscle because the
cells are long." Which observation would CORRECT this error?
A. The cells are multinucleated with peripheral nuclei
B. The cells are spindle-shaped with single central nuclei and lack striations, identifying
smooth muscle [CORRECT]
C. The cells branch and contain intercalated discs
D. The cells contain Nissl bodies and long axons
Correct Answer: B
Rationale: The esophagus wall contains smooth muscle — spindle-shaped, uninucleate,
and non-striated; multinucleation indicates skeletal muscle, branching with discs
indicates cardiac muscle, and Nissl bodies indicate neurons.
