Answer:
The steps indicate the transmission of nerve impulse to skeletal muscles and contraction of sarcomere.
Explanation:
Muscle contraction is an anatomical and physiological alteration occurs in response to a biochemical pathway. Here is the contraction of single contractile unit (sarcomere) of muscle is discussed. Muscle contract in a way of all or none.
1) An impulse is conducted along the sarcolemma and then deep into the muscle fiber by the T tubule
2) Acetylocholine is released into the synaptic cleft and diffuses across it.
3) The sarcoplasmic reticulum releases calcium ions which diffuse into the sarcoplasm around the myofibril and bind to troponin.
4) Myosin cross bridges bind to Actin and contract
5) The troponin-tropomyosin complex moves exposing active sites on Actin
