Starting with the arrival of an action potential at the neuromuscular junction,which is the correct order of events?
A) Calcium is released from the sarcoplasmic reticulum,an action potential travels down the T tubule,depolarization spreads through the T tubule,and myosin binds actin.
B) An action potential travels down the T tubule,depolarization spreads through the T tubule,calcium is released from the sarcoplasmic reticulum,and myosin binds actin.
C) An action potential travels down the T tubule,depolarization spreads through the T tubule,calcium is taken up by the sarcoplasmic reticulum,and myosin binds actin.
D) An action potential travels down the T tubule,depolarization spreads through the T tubule,ATP binds to myosin,and myosin binds actin.
E) The T tubule is depolarized,calcium is released from the sarcoplasmic reticulum,an action potential is created in the muscle cell,and myosin binds actin.

Question

Quizplus · Accepted Answer

The arrival of an action potential at the neuromuscular junction triggers the release of calcium from the sarcoplasmic reticulum, leading to an increase in calcium concentration in the cytoplasm. This allows for the depolarization of the T tubules, which in turn triggers the myosin to bind to actin and initiate muscle contraction. Therefore, the correct order of events is: action potential travels down the T tubule, depolarization spreads through the T tubule, calcium is released from the sarcoplasmic reticulum, and myosin binds actin. Option B is the only choice that follows this sequence.

Starting with the Arrival of an Action Potential at the Neuromuscular