1. A graded whole muscle contraction is produced in vivo primarily by variations in a. the strength of the fiber's 5. contraction.
b. the number of fibers that are contracting.
c. both of these.
d. neither of these.
2. The series-elastic component of muscle contraction is responsible for a. increased muscle shortening to 6. successive twitches.
b. a time delay between contraction and shortening.
c. the lengthening of muscle after contraction has ceased.
a. leg muscles b. arm muscles c. muscles that move the fingers d. muscles of the trunk
c. either isotonic or isometric contraction of intrafusal fibers.
a. thousands b. hundreds c. dozens d. two e. one
Spastic paralysis may occur when there is damage to a. the lower motor neurons.
b. the upper motor neurons.
c. either the lower or the upper motor neurons.
When a skeletal muscle shortens during contraction, which of these statements is false?
a. The A bands shorten.
b. The H bands shorten.
c. The I bands shorten.
b. attachment of the cross bridges to action.
d. splitting of ATP.
9. The energy for muscle contraction is most directly obtained from a. phosphocreatine.
c. anaerobic respiration.
10. Which of these statements about cross bridges is false?
a. They are composed of myosin.
b. They bind to ATP after they detach from actin.
c. They contain an ATPase.
d. They split ATP before they attach to actin.
11. When a muscle is stimulated to contract, Ca2+ binds to a. myosin.
12. Which of these statements about muscle fatigue is false?
a. It may result when ATP is no longer available for the cross-bridge cycle.
b. It may be caused by a loss of muscle cell Ca2+.
c. It may be caused by the accumulation of extracellular K+.
d. It may be a result of lactic acid production.
a. single-unit smooth muscle b. multiunit smooth muscle c. cardiac muscle d. skeletal muscle
15. In an isotonic muscle contraction, a. the length of the muscle remains constant.
b. the muscle tension remains constant.
c. both muscle length and tension are changed.
d. movement of bones does not occur.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.