Which of the following is NOT a major function of skeletal muscle? maintaining body temperature lining hollow organs maintaining posture storing nutrient reserves Answer: b
How would a drug that blocks acetylcholine release affect muscle contraction? Contraction would be prevented. Contraction would be slowed. The speed of contraction would increase. The strength of contraction would increase. Answer: a
Which of the following describe the characteristics of slow muscle fibers? small diameter, rich in myoglobin, and high glycogen reserve large diameter, very vascular, and multiple mitochondria small diameter, rich in myoglobin, and very vascular large diameter, high glycogen reserve, and lack significant myoglobin Answer: c
How would severing the tendon attached to a muscle affect the muscle’s ability to move a body part? Uncontrolled movement would result from a severed tendon. Movement would be greatly exaggerated with no tendon. No movement is possible without a muscle to bone connection. Limited movement would result. Answer: c
Which of these describes the neuromuscular junction? the surface containing membrane receptors that bind acetylcholine special intercellular connection between axon branches and a skeletal muscle fiber the link between generation of an action potential and the start of muscle contraction a propagated change in membrane potential that travels the length of an axon Answer: b
Myofibrils are organized into repeating subunits called _____. T tubules Z lines sarcomeres sarcoplasmic reticulum. Answer: c
Why does skeletal muscle appear striated when viewed through a microscope? Z lines and myosin filaments align within a muscle fiber. Glycogen reserves are linearly arranged. Capillaries regularly intersect the myofibers. Actin filaments repel stain, appearing banded. Answer: a
Where would you expect the greatest concentration of Ca2+ in resting skeletal muscle to be? in T tubules surrounding the mitochondria within sarcomeres in cisternae of the sarcoplasmic reticulum Answer: d
What is the mechanism that is primarily responsible for ATP production at peak levels of activity? the reaction between ADP and creatine aerobic metabolism in mitochondria glycolysis in the cytoplasm both B and C Answer: c
What would you expect to happen to a resting skeletal muscle if the sarcolemma suddenly became very permeable to Ca2+? increased strength of contraction decreased cross-bridge decreased ability to relax both A and C Answer: d
What structural characteristics distinguish cardiac muscle tissue from skeletal muscle tissue? Cardiac muscle cells _____. are larger and usually have one nucleus have intercalated discs, short T tubules, and no triads are dependent on anaerobic metabolism contact each other at tight junctions Answer: b
Why would a sprinter experience muscle fatigue before a marathon runner? Marathon running uses ATP for only a short time, while sprinting uses ATP indefinitely. Marathon runners’ muscles depend on stored glycogen; therefore, they do not fatigue. Sprinting involves anaerobic endurance, whereas running a marathon depends more upon availability of substrates for aerobic respiration. None of the above are correct. Answer: c