Where is Ca++ released during muscle contraction?

The hypopolarization of the T tubules opens special voltage-gated channels in opposing regions of the sarcoplasmic reticulum membrane. By an as yet incompletely understood mechanism, this leads to a release of calcium from the cisternae of the sarcoplasmic reticulum into the region of the myofilaments. This is an essential step in the contraction mechanism; muscles depleted of calcium do not contract. The calcium diffuses to the thin filaments and binds to troponin. Each head of the myosin molecule (a molecule has two) is an ATPase, capable of hydrolyzing ATP to ADP and inorganic phosphate, releasing energy; however, according to current thought, tropomyosin inhibits the ATPase. The combination of troponin with Ca++ removes the tropomyosin inhibition, perhaps by inducing a conformational change in the thin filament.

In a muscle move, the motor neurons enable in Ca++ which releases acetylcholine, which receives certain and actively transported right into a muscle cellular. The energetic shipping motives the absolutely move. So i wager for a contraction, because the Ca++ is interior the motor neuron in the time of a muscle move, it may get released from there too? i know Ca++ interacts with the motor neurons, yet I ignore no matter if it shifting into the neuron is for enlargement or contraction....