Describe the important steps in muscle contraction.

The important steps in muscle contraction start with the signal sent by the central nervous system via a motor neuron. Then next step when the neural signal reaches the neuro muscular junction is the release of neuro transmitter (Acetyl choline) which generates an action potential in the sarcolemma. The action potential spreads through the fibres and releases calcium ion into the sacroplasm. The Ca⁺⁺ ions bind with a submit of troponin on the action filaments and remove the Masking Myosin. The myosin binds with the action to form a cross bridge which pulls the action filaments towards the centre of A¹ band. The ‘Z’ line is pulled inwards and this shortens the sacromere which is the contraction of the muscle. The energy required for this purpose is obtained by the hydrolysis of ATP. When a new ATP which binds the cross bridge is broken, the muscle is relaxed followed by the cyclic contraction.