The structural theory that explains how a muscle fiber contracts is called the ________ theory.
A) sliding filament
B) excitation-contraction coupling
C) neuromuscular
D) muscle contraction
E) action-myosin interaction
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Question 2) The complex of a transverse tubule and two adjacent terminal cisternae is known as a
A) trimer.
B) triad.
C) triptych.
D) trisome.
E) trilogy.
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Question 3) Stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue are called
A) myocytes.
B) satellite cells.
C) endocytes.
D) sarcocytes.
E) creatinocytes.
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Question 4) Thick filaments are made of the protein
A) actin.
B) titin.
C) myosin.
D) tropomyosin.
E) nebulin.
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Question 5) Thin filaments are mostly made of the protein
A) actin.
B) titin.
C) myosin.
D) tropomyosin.
E) nebulin.
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Question 6) The protein that regulates muscle contraction by controlling the availability of active sites on actin is called
A) actin.
B) titin.
C) myosin.
D) tropomyosin.
E) nebulin.
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Question 7) The protein that is found in the Z line of a sarcomere is called
A) actinin.
B) titin.
C) nebulin.
D) myosin.
E) actin.
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Question 8) Physical evidence that supports the sliding filament theory of muscle contraction includes
A) constant distance between Z lines during contraction.
B) decreased width of the H band during contraction.
C) increased width of the I band during contraction.
D) decreased width of the A band during contraction.
E) the I band + H band distance is constant during contraction.
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Question 9) When calcium ion binds to troponin,
A) tropomyosin rolls away from the active site.
B) active sites on the myosin are exposed.
C) actin heads will bind to myosin.
D) muscle relaxation occurs.
E) myosin shortens.
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Question 10) The most important factor in decreasing the intracellular concentration of calcium ion after contraction is
A) active transport of calcium across the sarcolemma.
B) active transport of calcium into the sarcoplasmic reticulum.
C) active transport of calcium into the synaptic cleft.
D) diffusion of calcium out of the cell.
E) diffusion of calcium into the sarcoplasmic reticulum.
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