Which of the following statements correctly describe(s) T tubules and their role in conducting action potentials in muscle cells?
A. T tubules carry action potentials into the interior of the muscle cell via voltage-gated Na+ and K+ channels.
B. T tubules lack the voltage-gated Na+ and K+ channels that are present in the plasma membrane.
C. T tubules are infoldings of the plasma membrane that encircle the myofibrils and are in contact with the sarcoplasmic reticulum.
D. Without T tubules, the muscle cell would not be able to contract.
E. T tubules are extensions of the sarcoplasmic reticulum that are in contact with the plasma membrane.
F. T tubules have receptor proteins that bind neurotransmitters released from the synaptic terminal of the motor neuron.
Answer:
A. T tubules carry action potentials into the interior of the muscle cell via voltage-gated Na+ and K+ channels.
C. T tubules are infoldings of the plasma membrane that encircle the myofibrils and are in contact with the sarcoplasmic reticulum.
D. Without T tubules, the muscle cell would not be able to contract.
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