Define the following terms:
$(1)$ Sarcomere
$(2)$ Acromion process

In striated muscle contraction:

During muscular contraction,which of the following occurs?

Discuss the microscopic structure of skeletal muscle tissue.

Arrange the given steps of muscle contraction in the series of events from first to last.
$I.$ Myosin head binds to the exposed active site on actin to form a cross bridge.
$II.$ The $Z$-line attached to these actin are also pulled inwards,thereby causing shortening of sarcomere,also called contraction.
$III.$ This pulls the attached actin filaments towards the centre of $A$-band.
The correct option is:

Sarcolemma,sarcoplasm,and sarcoplasmic reticulum refer to a particular type of cell in our body. Which is this cell and to what parts of that cell do these names refer to?