Which statement most accurately describes the role of T tubules in skeletal muscle cells?A.T tubules bind acetylcholine at the neuromuscular junction to generate a depolarizing stimulus.B.Depolarizing current reaches the sarcoplasmic reticulum by traveling down T tubules.C.Muscle contraction is driven by the sliding of T tubules across one another in the sarcomere.D.T tubules sequester Ca2+ out of the cytosol to prevent prolonged muscle contraction.
Question
Which statement most accurately describes the role of T tubules in skeletal muscle cells?A.T tubules bind acetylcholine at the neuromuscular junction to generate a depolarizing stimulus.B.Depolarizing current reaches the sarcoplasmic reticulum by traveling down T tubules.C.Muscle contraction is driven by the sliding of T tubules across one another in the sarcomere.D.T tubules sequester Ca2+ out of the cytosol to prevent prolonged muscle contraction.
Solution
The statement that most accurately describes the role of T tubules in skeletal muscle cells is B. Depolarizing current reaches the sarcoplasmic reticulum by traveling down T tubules.
Here's why:
A. T tubules do not bind acetylcholine at the neuromuscular junction to generate a depolarizing stimulus. This is the role of the motor end plate.
B. This is correct. T tubules, or transverse tubules, are extensions of the cell membrane that penetrate into the centre of skeletal and cardiac muscle cells. These tubules allow depolarization of the membrane to quickly reach the interior of the cell and the sarcoplasmic reticulum, which stores calcium ions necessary for muscle contraction.
C. Muscle contraction is not driven by the sliding of T tubules across one another in the sarcomere. This statement describes the sliding filament theory, which involves the proteins actin and myosin, not T tubules.
D. T tubules do not sequester Ca2+ out of the cytosol to prevent prolonged muscle contraction. This is the role of the sarcoplasmic reticulum, not the T tubules.
Similar Questions
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