Physiology 3120 Lecture Notes - Lecture 9: Multinucleate, T-Tubule, Sarcomere

• School: Western University
• Department: Physiology
• Course: Physiology 3120
• Professor: Tom Stavraky

Document Summary

Whole muscle made up of tight bundles called fascicles. Fascicles are made up of individual muscle cells. Thin myofilaments: show up as lighter band. In relaxed muscle troponin is attached to tropomyosin and actin so that it holds the tropomyosin over the myosin binding sites until ca++ arrives! Calcium binds to the troponin c and then changes the shape of the troponin. The troponin will them get the tropomyosin of the myosin binding sites of actin. Thick myofilaments are made of individual myosin molecules: thick myofilament has many myosin molecules. Myosin head extends out to the side: binding site for atp: how the myosin gets its energy for muscle contraction. Titin helps keep the protein aligned: spring to help return the muscles/filaments back to original state when muscle relaxes, need to help keep aligned because if not aligned then cannot perform muscle contraction. Thin myofilaments: joined together by z-line, hold it in place.