BIOL 251 Module 5 Exam Review Human Anatomy & Physiology I with Lab 68 Questions with Correct Answers | 2026 Study Edition

BIOL 251 Module 5 Exam Review — Portage Learning 2026 Study Edition




BIOL 251 Module 5 Exam Review
Human Anatomy & Physiology I with Lab
68 Questions with Correct Answers | 2026 Study Edition
Original independent study & review materials — not affiliated with, endorsed by, or reproduced from Portage Learning.


Focus: Muscular System — Tissue Organization, Contraction Physiology, and Major Skeletal Muscles




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, BIOL 251 Module 5 Exam Review — Portage Learning 2026 Study Edition


SECTION I — QUESTIONS 1–68
Answer each question to the best of your ability before checking Section II. Diagram-labeling questions refer to the original
schematic figures provided.




Question 1 [Multiple Choice]
Which type of muscle tissue is striated, voluntary, and multinucleated?
☐ A. Skeletal muscle
☐ B. Cardiac muscle
☐ C. Smooth muscle
☐ D. Visceral muscle


Question 2 [Multiple Choice]
The connective tissue layer that surrounds an individual muscle fiber is called the:
☐ A. Epimysium
☐ B. Endomysium
☐ C. Perimysium
☐ D. Fascicle


Question 3 [Multiple Choice]
A bundle of muscle fibers wrapped by the perimysium is known as a:
☐ A. Sarcomere
☐ B. Myofilament
☐ C. Fascicle
☐ D. Tendon


Question 4 [Multiple Choice]
Which protein forms the thin filament of a sarcomere?
☐ A. Myosin
☐ B. Titin
☐ C. Troponin
☐ D. Actin


Question 5 [Multiple Choice]
During muscle contraction, which zone of the sarcomere narrows and can disappear entirely?
☐ A. H zone
☐ B. A band
☐ C. Z disc width
☐ D. Myosin filament length

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, BIOL 251 Module 5 Exam Review — Portage Learning 2026 Study Edition




Question 6 [Multiple Choice]
What triggers the release of acetylcholine at the neuromuscular junction?
☐ A. Sodium influx into the sarcoplasmic reticulum
☐ B. Arrival of an action potential at the axon terminal, causing calcium influx
☐ C. Binding of ATP to myosin heads
☐ D. Repolarization of the sarcolemma


Question 7 [Multiple Choice]
Acetylcholine released at the NMJ binds to receptors located on the:
☐ A. Presynaptic membrane
☐ B. T-tubule interior
☐ C. Motor end plate (sarcolemma)
☐ D. Sarcoplasmic reticulum membrane


Question 8 [Multiple Choice]
Which ion is released from the sarcoplasmic reticulum to initiate the interaction between actin and myosin?
☐ A. Sodium
☐ B. Potassium
☐ C. Chloride
☐ D. Calcium


Question 9 [Multiple Choice]
The role of tropomyosin in a resting muscle fiber is to:
☐ A. Block the myosin-binding sites on actin
☐ B. Bind calcium ions directly
☐ C. Hydrolyze ATP
☐ D. Transmit the action potential along the sarcolemma


Question 10 [Multiple Choice]
Rigor mortis occurs after death primarily because:
☐ A. Calcium is pumped rapidly back into the SR
☐ B. ATP is no longer available to detach myosin heads from actin
☐ C. Sodium channels remain permanently closed
☐ D. Acetylcholinesterase becomes hyperactive


Question 11 [Multiple Choice]
Which phase of a muscle twitch corresponds to calcium release and cross-bridge formation, but before measurable
tension develops?
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, BIOL 251 Module 5 Exam Review — Portage Learning 2026 Study Edition

☐ A. Refractory period
☐ B. Contraction period
☐ C. Latent period
☐ D. Relaxation period


Question 12 [Multiple Choice]
A motor unit consists of:
☐ A. One motor neuron and one muscle fiber
☐ B. A group of sarcomeres in series
☐ C. A fascicle bound by perimysium
☐ D. One motor neuron and all the muscle fibers it innervates


Question 13 [Multiple Choice]
Muscles that require fine motor control, such as those controlling the eyes, typically have:
☐ A. Small motor units with few fibers per neuron
☐ B. Large motor units with many fibers per neuron
☐ C. No motor units at all
☐ D. Only Type IIx fibers


Question 14 [Multiple Choice]
The primary immediate source of ATP for the first few seconds of intense muscle contraction is:
☐ A. Aerobic respiration
☐ B. Creatine phosphate
☐ C. Glycogen stores
☐ D. Anaerobic glycolysis


Question 15 [Multiple Choice]
Which energy system produces the most ATP per glucose molecule but requires oxygen?
☐ A. Anaerobic glycolysis
☐ B. Phosphocreatine system
☐ C. Aerobic (oxidative) respiration
☐ D. Lactic acid fermentation


Question 16 [Multiple Choice]
Muscle fatigue during prolonged, intense exercise is most closely associated with:
☐ A. Excess oxygen supply
☐ B. Increased calcium storage in the SR
☐ C. Permanent destruction of sarcomeres
☐ D. Depletion of ATP/glycogen and accumulation of metabolic byproducts


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