BIOS 252 Week 4 Midterm Exam | 2025|
Chamberlain University| Actual Exam
Questions and Correct Answers
Question 1
T Tubules are extensions of the _____ in skeletal muscle?
A. Sarcoplasmic reticulum
B. Sarcolemma
C. Myofibril
D. Mitochondria
Correct Answer: B. Sarcolemma
Explanation:
T-tubules (transverse tubules) are invaginations of the sarcolemma, the plasma membrane of
skeletal muscle cells. They allow rapid transmission of action potentials into the muscle cell to
trigger calcium release. The sarcoplasmic reticulum (A) stores calcium, myofibrils (C) are
contractile units, and mitochondria (D) produce energy, not extensions.
Question 2
CN III innervates which of the following muscles?
A. Lateral rectus
B. Superior oblique
C. Medial rectus
D. Buccinator
Correct Answer: C. Medial rectus
Explanation:
Cranial nerve III (oculomotor nerve) innervates most extraocular muscles, including the medial
rectus, which moves the eye medially. Lateral rectus (A) is innervated by CN VI, superior
oblique (B) by CN IV, and buccinator (D) is a facial muscle innervated by CN VII.
,Question 3
The brain and spinal cord are part of the ______ nervous system?
A. Peripheral nervous system
B. Central nervous system
C. Autonomic nervous system
D. Somatic nervous system
Correct Answer: B. Central nervous system
Explanation:
The central nervous system (CNS) consists of the brain and spinal cord, responsible for
processing and integrating information. The peripheral nervous system (A) includes nerves
outside the CNS, autonomic (C) controls involuntary functions, and somatic (D) controls
voluntary movements.
Question 4
A wheelbarrow is an example of a _______ class lever?
A. First-class lever
B. Second-class lever
C. Third-class lever
D. Fourth-class lever
Correct Answer: B. Second-class lever
Explanation:
A wheelbarrow is a second-class lever, where the load (effort) is between the fulcrum (wheel)
and the force (handles). First-class levers (A) have the fulcrum between load and force (e.g.,
seesaw). Third-class levers (C) have the force between fulcrum and load (e.g., tweezers). There
is no fourth-class lever (D).
Question 5
The muscle contraction pulling on its insertion point corresponds to what part of the lever
system?
A. Fulcrum
, B. Load
C. Effort
D. Lever arm
Correct Answer: C. Effort
Explanation:
In a lever system, the muscle’s force (contraction) pulling on its insertion point represents the
effort, applied to move the load (body part). The fulcrum (A) is the joint, the load (B) is the
weight moved, and the lever arm (D) is the bone.
Question 6
A synovial joint corresponds to what part of the lever system?
A. Load
B. Effort
C. Fulcrum
D. Lever arm
Correct Answer: C. Fulcrum
Explanation:
In the lever system of the body, the synovial joint acts as the fulcrum, the pivot point around
which movement occurs. The load (A) is the weight moved, effort (B) is the muscle force, and
lever arm (D) is the bone.
Question 7
When would voltage-gated sodium channels open rapidly?
A. During repolarization
B. During the resting membrane potential
C. During depolarization
D. During hyperpolarization
Correct Answer: C. During depolarization
Explanation:
Chamberlain University| Actual Exam
Questions and Correct Answers
Question 1
T Tubules are extensions of the _____ in skeletal muscle?
A. Sarcoplasmic reticulum
B. Sarcolemma
C. Myofibril
D. Mitochondria
Correct Answer: B. Sarcolemma
Explanation:
T-tubules (transverse tubules) are invaginations of the sarcolemma, the plasma membrane of
skeletal muscle cells. They allow rapid transmission of action potentials into the muscle cell to
trigger calcium release. The sarcoplasmic reticulum (A) stores calcium, myofibrils (C) are
contractile units, and mitochondria (D) produce energy, not extensions.
Question 2
CN III innervates which of the following muscles?
A. Lateral rectus
B. Superior oblique
C. Medial rectus
D. Buccinator
Correct Answer: C. Medial rectus
Explanation:
Cranial nerve III (oculomotor nerve) innervates most extraocular muscles, including the medial
rectus, which moves the eye medially. Lateral rectus (A) is innervated by CN VI, superior
oblique (B) by CN IV, and buccinator (D) is a facial muscle innervated by CN VII.
,Question 3
The brain and spinal cord are part of the ______ nervous system?
A. Peripheral nervous system
B. Central nervous system
C. Autonomic nervous system
D. Somatic nervous system
Correct Answer: B. Central nervous system
Explanation:
The central nervous system (CNS) consists of the brain and spinal cord, responsible for
processing and integrating information. The peripheral nervous system (A) includes nerves
outside the CNS, autonomic (C) controls involuntary functions, and somatic (D) controls
voluntary movements.
Question 4
A wheelbarrow is an example of a _______ class lever?
A. First-class lever
B. Second-class lever
C. Third-class lever
D. Fourth-class lever
Correct Answer: B. Second-class lever
Explanation:
A wheelbarrow is a second-class lever, where the load (effort) is between the fulcrum (wheel)
and the force (handles). First-class levers (A) have the fulcrum between load and force (e.g.,
seesaw). Third-class levers (C) have the force between fulcrum and load (e.g., tweezers). There
is no fourth-class lever (D).
Question 5
The muscle contraction pulling on its insertion point corresponds to what part of the lever
system?
A. Fulcrum
, B. Load
C. Effort
D. Lever arm
Correct Answer: C. Effort
Explanation:
In a lever system, the muscle’s force (contraction) pulling on its insertion point represents the
effort, applied to move the load (body part). The fulcrum (A) is the joint, the load (B) is the
weight moved, and the lever arm (D) is the bone.
Question 6
A synovial joint corresponds to what part of the lever system?
A. Load
B. Effort
C. Fulcrum
D. Lever arm
Correct Answer: C. Fulcrum
Explanation:
In the lever system of the body, the synovial joint acts as the fulcrum, the pivot point around
which movement occurs. The load (A) is the weight moved, effort (B) is the muscle force, and
lever arm (D) is the bone.
Question 7
When would voltage-gated sodium channels open rapidly?
A. During repolarization
B. During the resting membrane potential
C. During depolarization
D. During hyperpolarization
Correct Answer: C. During depolarization
Explanation:
