COMPREHENSIVE EXAM: BIOS255 / BIOS
255 (LATEST UPDATE 2026/2027) ANATOMY
& PHYSIOLOGY III WITH LAB | TEST
QUESTIONS & ANSWERS | 100% CORRECT |
GRADE A - CHAMBERLAIN
AT CHAMBERLAIN COLLEGE OF NURSING
Comprehensive Exam: BIOS255/BIOS 255 (2026/2027 Update) –
Anatomy & Physiology III with Lab
Question 1
Question: _____________ channels respond to changes in membrane potential.
Options:
A. Ligand-gated
B. Mechanically-gated
C. Voltage-gated
D. Leak channels
Answer: Voltage-gated
Rationale: Voltage-gated channels open or close in response to changes in the
electrical potential across the membrane. These channels are crucial in generating
and propagating action potentials in neurons and muscle fibers. Without voltage-gated
channels, rapid signaling in excitable tissues would be impossible.
Question 2
Question: Which of the following regulatory proteins covers the myosin-binding sites
on actin?
Options:
A. Troponin
,B. Tropomyosin
C. Myosin light chain
D. Actinin
Answer: Tropomyosin
Rationale: Tropomyosin is a filamentous protein that wraps around actin filaments,
covering the myosin-binding sites at rest. This prevents myosin from binding to actin
until calcium ions trigger a conformational change via troponin. It is essential for the
regulation of skeletal muscle contraction.
Question 3
Question: Calcium must bind to which protein to initiate muscle contraction?
Options:
A. Tropomyosin
B. Troponin
C. Myosin
D. Actin
Answer: Troponin
Rationale: Troponin binds calcium ions released from the sarcoplasmic reticulum,
which causes a shift in tropomyosin away from the myosin-binding sites on actin. This
allows cross-bridge formation between actin and myosin, leading to muscle
contraction. Troponin thus serves as the calcium sensor in skeletal muscle.
Question 4
Question: Which of the following muscles does not make up the rotator cuff?
Options:
A. Supraspinatus
B. Infraspinatus
C. Teres minor
D. Rhomboid major
,Answer: Rhomboid major
Rationale: The rotator cuff consists of the supraspinatus, infraspinatus, teres minor,
and subscapularis muscles. These muscles stabilize the glenohumeral joint and
facilitate rotation of the arm. Rhomboid major is a back muscle that retracts the
scapula and does not contribute to the rotator cuff.
Question 5
Question: Which of the following best describes the type of contraction in which a
muscle remains the same length as it maintains tension?
Options:
A. Isotonic concentric
B. Isotonic eccentric
C. Isometric
D. Tonic
Answer: Isometric
Rationale: In an isometric contraction, muscle fibers generate tension without
changing length. This type of contraction occurs when a muscle attempts to move a
load that is heavier than the tension it can generate. It is essential for posture
maintenance and stabilizing joints during movement.
Question 6
Question: Which division of the peripheral nervous system is responsible for sending
signals from the brain and spinal cord to effectors?
Options:
A. Afferent division
B. Efferent division
C. Somatic sensory division
D. Autonomic sensory division
Answer: Efferent division
Rationale: The efferent division carries motor commands from the CNS to muscles
, and glands (effectors). It is subdivided into the somatic nervous system, which
controls voluntary movements, and the autonomic nervous system, which regulates
involuntary functions. The afferent division, in contrast, carries sensory information to
the CNS.
Question 7
Question: During the depolarization phase of an action potential, which ion primarily
moves into the neuron?
Options:
A. Potassium (K⁺)
B. Sodium (Na⁺)
C. Calcium (Ca²⁺)
D. Chloride (Cl⁻)
Answer: Sodium (Na⁺)
Rationale: Depolarization occurs when voltage-gated sodium channels open, allowing
Na⁺ ions to rush into the neuron. This influx causes the membrane potential to
become more positive, initiating the action potential. The rapid change in potential is
essential for nerve signal propagation.
Question 8
Question: Which of the following is the primary neurotransmitter at neuromuscular
junctions?
Options:
A. Dopamine
B. Norepinephrine
C. Acetylcholine
D. Serotonin
Answer: Acetylcholine
Rationale: Acetylcholine is released from motor neurons at the neuromuscular
junction and binds to nicotinic receptors on the muscle fiber's motor endplate. This
255 (LATEST UPDATE 2026/2027) ANATOMY
& PHYSIOLOGY III WITH LAB | TEST
QUESTIONS & ANSWERS | 100% CORRECT |
GRADE A - CHAMBERLAIN
AT CHAMBERLAIN COLLEGE OF NURSING
Comprehensive Exam: BIOS255/BIOS 255 (2026/2027 Update) –
Anatomy & Physiology III with Lab
Question 1
Question: _____________ channels respond to changes in membrane potential.
Options:
A. Ligand-gated
B. Mechanically-gated
C. Voltage-gated
D. Leak channels
Answer: Voltage-gated
Rationale: Voltage-gated channels open or close in response to changes in the
electrical potential across the membrane. These channels are crucial in generating
and propagating action potentials in neurons and muscle fibers. Without voltage-gated
channels, rapid signaling in excitable tissues would be impossible.
Question 2
Question: Which of the following regulatory proteins covers the myosin-binding sites
on actin?
Options:
A. Troponin
,B. Tropomyosin
C. Myosin light chain
D. Actinin
Answer: Tropomyosin
Rationale: Tropomyosin is a filamentous protein that wraps around actin filaments,
covering the myosin-binding sites at rest. This prevents myosin from binding to actin
until calcium ions trigger a conformational change via troponin. It is essential for the
regulation of skeletal muscle contraction.
Question 3
Question: Calcium must bind to which protein to initiate muscle contraction?
Options:
A. Tropomyosin
B. Troponin
C. Myosin
D. Actin
Answer: Troponin
Rationale: Troponin binds calcium ions released from the sarcoplasmic reticulum,
which causes a shift in tropomyosin away from the myosin-binding sites on actin. This
allows cross-bridge formation between actin and myosin, leading to muscle
contraction. Troponin thus serves as the calcium sensor in skeletal muscle.
Question 4
Question: Which of the following muscles does not make up the rotator cuff?
Options:
A. Supraspinatus
B. Infraspinatus
C. Teres minor
D. Rhomboid major
,Answer: Rhomboid major
Rationale: The rotator cuff consists of the supraspinatus, infraspinatus, teres minor,
and subscapularis muscles. These muscles stabilize the glenohumeral joint and
facilitate rotation of the arm. Rhomboid major is a back muscle that retracts the
scapula and does not contribute to the rotator cuff.
Question 5
Question: Which of the following best describes the type of contraction in which a
muscle remains the same length as it maintains tension?
Options:
A. Isotonic concentric
B. Isotonic eccentric
C. Isometric
D. Tonic
Answer: Isometric
Rationale: In an isometric contraction, muscle fibers generate tension without
changing length. This type of contraction occurs when a muscle attempts to move a
load that is heavier than the tension it can generate. It is essential for posture
maintenance and stabilizing joints during movement.
Question 6
Question: Which division of the peripheral nervous system is responsible for sending
signals from the brain and spinal cord to effectors?
Options:
A. Afferent division
B. Efferent division
C. Somatic sensory division
D. Autonomic sensory division
Answer: Efferent division
Rationale: The efferent division carries motor commands from the CNS to muscles
, and glands (effectors). It is subdivided into the somatic nervous system, which
controls voluntary movements, and the autonomic nervous system, which regulates
involuntary functions. The afferent division, in contrast, carries sensory information to
the CNS.
Question 7
Question: During the depolarization phase of an action potential, which ion primarily
moves into the neuron?
Options:
A. Potassium (K⁺)
B. Sodium (Na⁺)
C. Calcium (Ca²⁺)
D. Chloride (Cl⁻)
Answer: Sodium (Na⁺)
Rationale: Depolarization occurs when voltage-gated sodium channels open, allowing
Na⁺ ions to rush into the neuron. This influx causes the membrane potential to
become more positive, initiating the action potential. The rapid change in potential is
essential for nerve signal propagation.
Question 8
Question: Which of the following is the primary neurotransmitter at neuromuscular
junctions?
Options:
A. Dopamine
B. Norepinephrine
C. Acetylcholine
D. Serotonin
Answer: Acetylcholine
Rationale: Acetylcholine is released from motor neurons at the neuromuscular
junction and binds to nicotinic receptors on the muscle fiber's motor endplate. This
