ANP 1105 Lecture Notes - Lecture 5: Skeletal Muscle, Phosphate, Myosin Head

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Jackie Carnegie

Document Summary

Functional unit of contraction is the sarcomeres sarcomeres shortens heads in thick in thick myofilaments form cross bridges with active molecules and thin myofilaments. The formation of a cross bridge is initiated when calcium ions, released from the sarcoplasmic reticulum, bind to tropinon. Tropinin then changes shape. tropmysoin moves away from the binding sites on actin. Allowing the myosin head to bind on actin forming a cross bridge. Myosin head must be activated before atp binds to myosin which then gets hydrolyzed. Energy liberated activates the mysonhead in the cocked position. Can be divided into 4 stps: cross bridge formation the activated myosin head binds to actin forming a cross-bridge. Bond becomes stronger: the power stroke- adp is released then the myosin head pivots. As long as the binding sites on actin remains exposed, the cross bridge cycle repeats.