Sliding Filament Model

What is the sliding filament model of muscle contraction: what is mobile, which causes it to slide, the ions must be present, which is the contractile unit of skeletal muscle called?

is the contractile unit called sarcomere contains two main myofilaments called actin and myosin. Is this the actin and myosin that slide over each other for a muscle contraction to occur.
for this (slippage) of myosin and actin to bind together and running a process called "power" of the myosin filaments slide past actin.
Calcium is the main ion necessary for myosin actin binding because it allows the discovery of binding sites of tropomyosin in troponin.

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