51) Myofascial pain syndrome is best described as a condition in which
A) microscopic tears in muscle fibers result in swelling and inflammation.
B) muscle fibers degenerate because of chronic leakage of extracellular calcium.
C) muscle fibers contract when the skin superficial to them is stroked.
D) pain occurs in at least 11 of 18 standardized points across the body.
52) Age-related loss of muscle mass may be influenced by all of these
except:
A) an increase in the relative proportion of connective tissue to number of muscle fibers.
B) decrease in the level of testosterone.
C) degeneration of muscle fibers because of accumulation of calcium in the sarcoplasm.
D) exhaustion of the supply of muscle satellite cells.
53) Acetylcholine
A) binds to the myosin head, enabling it to form cross-bridges with actin.
B) binds to the sarcolemma and initiates an impulse in the muscle fiber.
C) breaks down the neurotransmitter that activates muscle fibers.
D) is released from the sarcoplasmic reticulum and binds to actin.
54) The sleevelike tubular network within skeletal muscle cells is the
A) sarcoplasmic reticulum.
B) rough endoplasmic reticulum.
C) myofibrils.
D) T tubules.
55) The type of attachment in which the muscle fibers seem to attach directly to a bone is
A) a tendon.
B) an aponeurosis.
C) an insertion.
D) a fleshy attachment.
56) Which region of the sarcomere does
not
change in length during contraction?
A) A band
B) H zone
C) I band
D) Z disk to Z disk
57) In limbs, the insertions of muscles almost always lie ________ to their origins.
A) proximal
B) distal
C) lateral
D) posterior
58) When the distance between two adjacent Z disks grows shorter, the muscle fiber is experiencing
A) concentric contraction.
B) eccentric contraction.
C) isometric contraction.
D) relaxation.
59) The ability of the sarcolemma of muscle cells to conduct an impulse is an example of
A) contractility.
B) excitability.
C) extensibility.
D) elasticity.
60) The characteristic of muscle tissue that results more from its connective tissue components than from its muscle cells is
A) contractility.
B) excitability.
C) extensibility.
D) elasticity.