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UWSP BIO 385 Exam 2 Study Guide:
Bray Human Physiology (2025-2026)
Prepare for UWSP BIO 385 Human Physiology Exam 2
with this focused study guide covering Dr. Bray's key
topics. Includes practice questions and definitions on
skeletal muscle contraction, sarcomere structure,
neuromuscular junctions, action potentials, synapses,
cardiac and smooth muscle, spinal cord reflexes, and the
autonomic nervous system. Ideal for reviewing motor
units, tetanus, EPPs, and ANS functions using
Sherwood's Human Physiology. Concise, searchable, and
aligned with the Fall course schedule.
1. Which of the following is the functional unit of a skeletal muscle
fiber?
A. Myofibril
B. Sarcomere
C. Myofilament
D. Motor unit
B. Sarcomere
The sarcomere is the smallest functional contractile unit of a muscle
fiber, extending from one Z line to the next.
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2. The A band of a sarcomere corresponds to the length of which
structure?
A. Actin only
B. Myosin only
C. Both actin and myosin overlap
D. The entire thick filament including the bare zone
D. The entire thick filament including the bare zone
The A band represents the full length of the thick (myosin)
filaments, including the region where actin and myosin overlap and
the H zone where only myosin is present.
3. During the power stroke of skeletal muscle contraction, what
happens?
A. Myosin heads detach from actin
B. Myosin heads pivot and pull actin toward the M line
C. Calcium is reuptaken into the sarcoplasmic reticulum
D. ATP binds to the myosin head
B. Myosin heads pivot and pull actin toward the M line
The power stroke occurs when the myosin head, bound to actin,
pivots and pulls the thin filament toward the center of the
sarcomere, shortening the muscle.
4. What is the role of acetylcholinesterase (AChE) at the
neuromuscular junction?
A. It synthesizes acetylcholine
B. It packages acetylcholine into vesicles
C. It degrades acetylcholine in the synaptic cleft
D. It binds acetylcholine to receptors on the motor end plate
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C. It degrades acetylcholine in the synaptic cleft
AChE breaks down acetylcholine in the synaptic cleft, terminating
the signal and preventing continuous muscle stimulation.
5. Which of the following best describes an end plate potential
(EPP)?
A. A graded depolarization of the motor end plate caused by
acetylcholine binding
B. An action potential propagating along the sarcolemma
C. A hyperpolarization caused by chloride influx
D. A repolarization event caused by potassium efflux
A. A graded depolarization of the motor end plate caused by
acetylcholine binding
The EPP is a graded depolarization of the motor end plate resulting
from sodium influx through nicotinic acetylcholine receptors.
6. What is a motor unit?
A. A single muscle fiber and its surrounding connective tissue
B. A motor neuron and all the muscle fibers it innervates
C. A group of sarcomeres within a myofibril
D. The region of the sarcolemma beneath the axon terminal
B. A motor neuron and all the muscle fibers it innervates
A motor unit consists of one motor neuron and all the muscle fibers
it stimulates.
7. Which of the following occurs during the latent period of a
muscle twitch?
A. The muscle visibly shortens
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B. Calcium is released and action potentials spread through the T-
tubules
C. The muscle relaxes as calcium is pumped back
D. Myosin heads complete the power stroke
B. Calcium is released and action potentials spread through the T-
tubules
The latent period is the brief delay between stimulation and the
onset of contraction, during which excitation-contraction coupling
occurs.
8. What is tetanus in the context of muscle physiology?
A. A bacterial infection of muscle tissue
B. A sustained contraction with no relaxation due to rapid stimulation
C. A single brief muscle twitch
D. The relaxation phase of a muscle twitch
B. A sustained contraction with no relaxation due to rapid
stimulation
Tetanus is a sustained maximal contraction resulting from high-
frequency stimulation that prevents the muscle from relaxing
between stimuli.
9. What is meant by asynchronous recruitment of motor units?
A. All motor units are activated simultaneously
B. Motor units are activated in a rotating fashion to sustain contraction
without fatigue
C. Only the largest motor units are activated first
D. Motor units are deactivated during contraction
B. Motor units are activated in a rotating fashion to sustain
contraction without fatigue
Asynchronous recruitment involves alternating activation of
UWSP BIO 385 Exam 2 Study Guide:
Bray Human Physiology (2025-2026)
Prepare for UWSP BIO 385 Human Physiology Exam 2
with this focused study guide covering Dr. Bray's key
topics. Includes practice questions and definitions on
skeletal muscle contraction, sarcomere structure,
neuromuscular junctions, action potentials, synapses,
cardiac and smooth muscle, spinal cord reflexes, and the
autonomic nervous system. Ideal for reviewing motor
units, tetanus, EPPs, and ANS functions using
Sherwood's Human Physiology. Concise, searchable, and
aligned with the Fall course schedule.
1. Which of the following is the functional unit of a skeletal muscle
fiber?
A. Myofibril
B. Sarcomere
C. Myofilament
D. Motor unit
B. Sarcomere
The sarcomere is the smallest functional contractile unit of a muscle
fiber, extending from one Z line to the next.
,2|Page
2. The A band of a sarcomere corresponds to the length of which
structure?
A. Actin only
B. Myosin only
C. Both actin and myosin overlap
D. The entire thick filament including the bare zone
D. The entire thick filament including the bare zone
The A band represents the full length of the thick (myosin)
filaments, including the region where actin and myosin overlap and
the H zone where only myosin is present.
3. During the power stroke of skeletal muscle contraction, what
happens?
A. Myosin heads detach from actin
B. Myosin heads pivot and pull actin toward the M line
C. Calcium is reuptaken into the sarcoplasmic reticulum
D. ATP binds to the myosin head
B. Myosin heads pivot and pull actin toward the M line
The power stroke occurs when the myosin head, bound to actin,
pivots and pulls the thin filament toward the center of the
sarcomere, shortening the muscle.
4. What is the role of acetylcholinesterase (AChE) at the
neuromuscular junction?
A. It synthesizes acetylcholine
B. It packages acetylcholine into vesicles
C. It degrades acetylcholine in the synaptic cleft
D. It binds acetylcholine to receptors on the motor end plate
,3|Page
C. It degrades acetylcholine in the synaptic cleft
AChE breaks down acetylcholine in the synaptic cleft, terminating
the signal and preventing continuous muscle stimulation.
5. Which of the following best describes an end plate potential
(EPP)?
A. A graded depolarization of the motor end plate caused by
acetylcholine binding
B. An action potential propagating along the sarcolemma
C. A hyperpolarization caused by chloride influx
D. A repolarization event caused by potassium efflux
A. A graded depolarization of the motor end plate caused by
acetylcholine binding
The EPP is a graded depolarization of the motor end plate resulting
from sodium influx through nicotinic acetylcholine receptors.
6. What is a motor unit?
A. A single muscle fiber and its surrounding connective tissue
B. A motor neuron and all the muscle fibers it innervates
C. A group of sarcomeres within a myofibril
D. The region of the sarcolemma beneath the axon terminal
B. A motor neuron and all the muscle fibers it innervates
A motor unit consists of one motor neuron and all the muscle fibers
it stimulates.
7. Which of the following occurs during the latent period of a
muscle twitch?
A. The muscle visibly shortens
, 4|Page
B. Calcium is released and action potentials spread through the T-
tubules
C. The muscle relaxes as calcium is pumped back
D. Myosin heads complete the power stroke
B. Calcium is released and action potentials spread through the T-
tubules
The latent period is the brief delay between stimulation and the
onset of contraction, during which excitation-contraction coupling
occurs.
8. What is tetanus in the context of muscle physiology?
A. A bacterial infection of muscle tissue
B. A sustained contraction with no relaxation due to rapid stimulation
C. A single brief muscle twitch
D. The relaxation phase of a muscle twitch
B. A sustained contraction with no relaxation due to rapid
stimulation
Tetanus is a sustained maximal contraction resulting from high-
frequency stimulation that prevents the muscle from relaxing
between stimuli.
9. What is meant by asynchronous recruitment of motor units?
A. All motor units are activated simultaneously
B. Motor units are activated in a rotating fashion to sustain contraction
without fatigue
C. Only the largest motor units are activated first
D. Motor units are deactivated during contraction
B. Motor units are activated in a rotating fashion to sustain
contraction without fatigue
Asynchronous recruitment involves alternating activation of
