Skin in Action
A student scrapes only the outermost layer of skin. The scrape stings but does not bleed. Which explanation fits best?
A. The epidermis has no blood vessels
B. The dermis blocks blood flow
C. The hypodermis seals the wound
D. Sweat glands close nearby vessels
A. The epidermis has no blood vessels
Which set contains only bones of the axial skeleton?
A. Skull, ribs, vertebral column
B. Scapula, humerus, radius
C. Pelvis, femur, patella
D. Clavicle, ulna, tibia
A. Skull, ribs, vertebral column
Which muscle tissue pushes food through the digestive tract?
A. Cartilage
B. Cardiac
C. Skeletal
D. Smooth
D. Smooth
A student completes 30, 24, and 18 repetitions across three equal trials. What pattern does the data show?
A. Performance increased
B. Performance decreased
C. Performance stayed constant
D. The resistance increased
B. Performance decreased
Which structure transfers force from a contracting quadriceps muscle to a bone?
A. Tendon
B. Ligament
C. Cartilage
D. Epidermis
A. Tendon
During a hot soccer practice, sweat spreads across a player's skin. How does this help lower body temperature?
A. Sweat traps cool air under the epidermis
B. Evaporation carries heat away from the skin
C. Sweat increases melanin production
D. Oil glands reduce blood flow to the skin
B. Evaporation carries heat away from the skin
A ligament in the ankle is overstretched. Which connection has been damaged?
A. Muscle to bone
B. Bone to bone
C. Cartilage to muscle
D. Skin to bone
B. Bone to bone
A muscle stretches as a student reaches toward the floor without being damaged. Which property is shown?
A. Contractility
B. Excitability
C. Extensibility
D. Elasticity
C. Extensibility
Two groups compare grip fatigue. Which variable should remain the same for a fair test?
A. The resistance used
B. The students' final repetition count
C. Whether fatigue occurs
D. The conclusion written
A. The resistance used
A person cannot sweat normally after a skin injury. Which homeostatic problem is most likely during exercise?
A. Body temperature may rise too high
B. Bones will stop storing minerals
C. The heart becomes voluntary
D. Ligaments will shorten
A. Body temperature may rise too high
A cut damages sensory receptors and small blood vessels but does not reach the fat layer. Which region was injured?
A. Epidermis
B. Dermis
C. Hypodermis
D. Nail plate
B. Dermis
Why can worn knee cartilage make walking painful even if no bone is fractured?
A. The femur stops making blood cells
B. The ligament turns into muscle
C. The patella becomes part of the axial skeleton
D. The joint loses its smooth, shock-absorbing surface
D. The joint loses its smooth, shock-absorbing surface
Which sequence correctly moves from largest to smallest?
A. Whole muscle, fascicle, muscle fiber, myofibril, sarcomere
B. Whole muscle, muscle fiber, fascicle, sarcomere, myofibril
C. Fascicle, whole muscle, myofibril, muscle fiber, sarcomere
D. Whole muscle, myofibril, fascicle, muscle fiber, sarcomere
A. Whole muscle, fascicle, muscle fiber, myofibril, sarcomere
A student's repetitions are 22, 23, and 22. The prediction said repetitions would decrease. What should the student conclude?
A. The prediction was supported
B. Trial 2 should be deleted
C. The data show no clear decrease, so the prediction was not supported
D. The numbers should be adjusted to show fatigue
C. The data show no clear decrease, so the prediction was not supported
A runner pushes off the ground to begin a sprint. Which muscle and movement are most directly involved?
A. Rectus abdominis and knee flexion
B. Biceps and elbow extension
C. Gastrocnemius and plantar flexion
D. Deltoid and trunk rotation
C. Gastrocnemius and plantar flexion
A patient has a large, deep burn. Which pair of problems is most directly caused by losing normal skin functions?
A. Faster bone growth and fever
B. Increased oxygen delivery and sweating
C. Stronger sensation and heat retention
D. Dehydration and infection
D. Dehydration and infection
A disorder greatly reduces red bone marrow activity. Which skeletal function is most directly affected?
A. Storing fat under the skin
B. Moving food through the intestine
C. Producing blood cells
D. Cooling the body through sweat
C. Producing blood cells
When a person straightens the elbow, what happens to the main opposing muscles?
A. Biceps contracts while triceps relaxes
B. Triceps contracts while biceps relaxes
C. Both contract equally
D. Both become smooth muscle
B. Triceps contracts while biceps relaxes
Group A rests 30 seconds between trials. Group B rests 3 minutes. Why is it difficult to compare their fatigue results?
A. Muscles never recover during rest
B. Repetitions cannot measure performance
C. Both groups used the same dependent variable
D. Rest time is a an outside influence
D. Rest time is a an outside influence
A deep wound damages the dermis and a tendon beneath it. Which two effects are most likely?
A. Improved sensation plus reduced infection risk
B. Loss of melanin plus increased blood-cell production
C. No bleeding plus faster joint movement
D. Bleeding plus reduced transfer of muscle force to bone
D. Bleeding plus reduced transfer of muscle force to bone
Two people spend the same amount of time in strong sunlight. One has more melanin. Which conclusion is most accurate?
A. More melanin prevents all UV damage
B. Melanin repairs DNA after UV damage
C. Melanin reduces UV exposure to cell DNA, but protection is incomplete
D. Melanin cools skin by increasing sweat
C. Melanin reduces UV exposure to cell DNA, but protection is incomplete
An injury damages the pelvis. Which combination of skeletal functions could be affected most directly?
A. Hormone release and hearing
B. Digestion and gas exchange
C. Support, protection, and movement
D. Sweat production and UV protection
C. Support, protection, and movement
Which explanation best connects sarcomere shortening to movement of a bone?
A. The bone shortens inside the muscle
B. The ligament contracts and pulls the muscle
C. Sarcomeres push cartilage directly
D. Shortening spreads through myofibrils and fibers, the whole muscle shortens, and the tendon pulls bone
D. Shortening spreads through myofibrils and fibers, the whole muscle shortens, and the tendon pulls bone
Trial results are 36, 31, and 25 repetitions. Which statement uses the strongest evidence?
A. The student became tired
B. The activity was difficult
C. Trial 3 proves every muscle fatigues at the same rate
D. Repetitions fell by 11 from Trial 1 to Trial 3, supporting muscle fatigue
D. Repetitions fell by 11 from Trial 1 to Trial 3, supporting muscle fatigue
After repeated calf raises, a student's performance drops. Which chain best explains the visible movement and the measured fatigue?
A. Bone marrow shortens the gastrocnemius
B. The epidermis pulls the femur while smooth muscle relaxes
C. Sarcomeres shorten, the muscle pulls through a tendon, and repeated output eventually declines
D. Ligaments contract, cartilage shortens, and bones produce sweat
C. Sarcomeres shorten, the muscle pulls through a tendon, and repeated output eventually declines