1. Excitation–Contraction Coupling
Excitation–Contraction Coupling. Actin and myosin form sarcomere structures in skeletal muscle as shown. The influx of calcium ions (Ca2+) allows myosin heads from thick filaments to bind to the actin filaments. Ca2+ also activates myosin head cross-bridge cycling, leading to force generation and, ultimately, shortening of the sarcomere. Shortening of multiple sarcomeres leads to muscle contraction. The process is similar in cardiac and smooth muscle contraction, although structural organization and regulation differ. ADP, adenosine diphosphate; ATP, adenosine triphosphate. [Reproduced with permission from Kibble JD and Halsey CR: The Big Picture: Medical Physiology, 1st edition, McGraw-Hill, 2009.]
Source: Chapter 12. Muscles and Motility, The Big Picture: Medical Biochemistry
Citation: Janson LW, Tischler ME. The Big Picture: Medical Biochemistry; 2012 Available at: Accessed: November 03, 2017
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