'Gastrocnemius' is a muscle of

Mainly,skeletal muscles are named on the basis of:

The dark bands ($A$-bands) of a skeletal muscle are known as

Arrange the following steps of muscle contraction in the sequence of events occurring first:
$I.$ Receptor sites on sarcolemma
$II.$ Nerve impulse
$III.$ Release of $Ca^{2+}$
$IV.$ Acetylcholine release
$V.$ Shortening of sarcomere
$VI.$ Synaptic cleft
$VII.$ Spread of impulse over sarcolemma on $T$-tubule
The correct option is:

Sliding filament theory was given by

Which of the following ions is essential for muscular contraction?