n this module we discuss the significance of skeletal muscle contraction and the mechanism of contraction. Skeletal muscle contraction is involved in effector function (e.g. respiratory muscle contraction in ventilation in regulating PO2 and PCO2), in general body movement (e.g. maintaining posture, flexing and distending limbs), and to generate heat (byproduct of ATP hydrolysis in the process of contraction). The structural entities involved in muscle contraction include neuromuscular junction, presence of voltage-gated ion channels in the sarcolemma, T-tubules, sarcoplasmic reticulum and myofibrils.