,BIOS 252 Final Exam Anatomy & Physiology II Questions And
Answers 2026/2027 Chamberlain
1.** Which of the following are the three types of muscle tissue?
A) Skeletal, cardiac, and smooth
B) Skeletal, cardiac, and striated
C) Voluntary, involuntary, and cardiac
D) Striated, non-striated, and smooth
**Correct Answer:** A) Skeletal, cardiac, and smooth
**Rationale:** The three types of muscle tissue are skeletal (striated,
voluntary), cardiac (striated, involuntary), and smooth (non-striated,
involuntary).
**2.** Which type of muscle tissue is under voluntary control?
A) Skeletal muscle
B) Cardiac muscle
C) Smooth muscle
D) Both cardiac and smooth muscle
**Correct Answer:** A) Skeletal muscle
**Rationale:** Skeletal muscle is under voluntary (conscious) control. Cardiac
muscle (B) and smooth muscle (C) are involuntary (controlled by the
autonomic nervous system).
,**3.** Which of the following is the functional unit of a skeletal muscle fiber?
A) Myofibril
B) Sarcomere
C) Myosin
D) Actin
**Correct Answer:** B) Sarcomere
**Rationale:** The sarcomere is the functional unit of skeletal muscle
contraction, extending from one Z-disc to the next. Myofibrils (A) are
composed of sarcomeres; myosin (C) and actin (D) are the contractile
proteins within sarcomeres.
**4.** The sliding filament theory of muscle contraction describes:
A) Thick filaments sliding past thin filaments, shortening the sarcomere
B) Thin filaments sliding past thick filaments, shortening the sarcomere
C) Both thick and thin filaments shortening
D) Neither filament changing length
**Correct Answer:** B) Thin filaments sliding past thick filaments, shortening
the sarcomere
**Rationale:** The sliding filament theory proposes that thin filaments (actin)
slide past thick filaments (myosin), pulling the Z-discs closer together and
shortening the sarcomere. Neither filament changes length (D).
, **5.** Which protein is responsible for the "power stroke" during muscle
contraction?
A) Actin
B) Myosin
C) Troponin
D) Tropomyosin
**Correct Answer:** B) Myosin
**Rationale:** The myosin head undergoes a conformational change (power
stroke) that pulls the thin filament toward the center of the sarcomere. Actin
(A) is the thin filament; troponin (C) and tropomyosin (D) are regulatory
proteins.
**6.** Calcium ions bind to which protein to initiate muscle contraction?
A) Actin
B) Myosin
C) Troponin
D) Tropomyosin
**Correct Answer:** C) Troponin
**Rationale:** Calcium ions bind to troponin, causing a conformational
change that moves tropomyosin away from the myosin-binding sites on
actin. This allows myosin heads to bind to actin and initiate contraction.
**7.** The neurotransmitter released at the neuromuscular junction is:
Answers 2026/2027 Chamberlain
1.** Which of the following are the three types of muscle tissue?
A) Skeletal, cardiac, and smooth
B) Skeletal, cardiac, and striated
C) Voluntary, involuntary, and cardiac
D) Striated, non-striated, and smooth
**Correct Answer:** A) Skeletal, cardiac, and smooth
**Rationale:** The three types of muscle tissue are skeletal (striated,
voluntary), cardiac (striated, involuntary), and smooth (non-striated,
involuntary).
**2.** Which type of muscle tissue is under voluntary control?
A) Skeletal muscle
B) Cardiac muscle
C) Smooth muscle
D) Both cardiac and smooth muscle
**Correct Answer:** A) Skeletal muscle
**Rationale:** Skeletal muscle is under voluntary (conscious) control. Cardiac
muscle (B) and smooth muscle (C) are involuntary (controlled by the
autonomic nervous system).
,**3.** Which of the following is the functional unit of a skeletal muscle fiber?
A) Myofibril
B) Sarcomere
C) Myosin
D) Actin
**Correct Answer:** B) Sarcomere
**Rationale:** The sarcomere is the functional unit of skeletal muscle
contraction, extending from one Z-disc to the next. Myofibrils (A) are
composed of sarcomeres; myosin (C) and actin (D) are the contractile
proteins within sarcomeres.
**4.** The sliding filament theory of muscle contraction describes:
A) Thick filaments sliding past thin filaments, shortening the sarcomere
B) Thin filaments sliding past thick filaments, shortening the sarcomere
C) Both thick and thin filaments shortening
D) Neither filament changing length
**Correct Answer:** B) Thin filaments sliding past thick filaments, shortening
the sarcomere
**Rationale:** The sliding filament theory proposes that thin filaments (actin)
slide past thick filaments (myosin), pulling the Z-discs closer together and
shortening the sarcomere. Neither filament changes length (D).
, **5.** Which protein is responsible for the "power stroke" during muscle
contraction?
A) Actin
B) Myosin
C) Troponin
D) Tropomyosin
**Correct Answer:** B) Myosin
**Rationale:** The myosin head undergoes a conformational change (power
stroke) that pulls the thin filament toward the center of the sarcomere. Actin
(A) is the thin filament; troponin (C) and tropomyosin (D) are regulatory
proteins.
**6.** Calcium ions bind to which protein to initiate muscle contraction?
A) Actin
B) Myosin
C) Troponin
D) Tropomyosin
**Correct Answer:** C) Troponin
**Rationale:** Calcium ions bind to troponin, causing a conformational
change that moves tropomyosin away from the myosin-binding sites on
actin. This allows myosin heads to bind to actin and initiate contraction.
**7.** The neurotransmitter released at the neuromuscular junction is:
