Differences and similarities between skeletal and cardiac muscle
“The Frank-Starling law of the heart applies to all classes of vertebrates” (Shiels et al., 2008, p.2005). Because myocyte stretch causes a more forceful systolic contraction, the Frank-Starling Law predicts that the stroke volume of the left ventricle will increase as the left ventricular volume increases (Shiels et al., 2008). The striated appearance of cardiac and skeletal muscle is similar. Skeletal muscle is voluntary, but cardiac muscle is involuntary. Skeletal muscles are attached to the carcass, the bones of our body. These muscles are responsible for the movement of the skeleton. Cardiac muscles are responsible for pumping blood to organ tissues. In cardiac muscle within the intercalated discs, gap junctions allow impulses to propagate from one cardiac muscle cell to another, allowing ions to move between adjacent cells, spreading the electrical impulse to contract, and ensuring synchronized contractions. Skeletal muscles work by a slightly different principle. When an action potential arrives at the axon terminal, calcium triggers neurotransmitter acetylcholine to be released, which triggers membrane depolarization in series of steps. Frank-Starling law shows how stretching cardiac muscle to its maximum length enhances contractility, connecting cardiac ejection and cardiac filling (Smith et al., 2011). In comparison to skeletal muscles, it follows a similar principle. When skeletal muscles are stretched, the force of the muscle increases significantly, and the magnitude of the twitch contraction increases immediately (Shiels et al., 2008, p.2006).
Shiels, & White, E. (2008). The Frank-Starling mechanism in vertebrate cardiac myocytes. Journal of Experimental Biology, 211(Pt 13), 2005–2013. https://doi.org/10.1242/jeb.003145
Smith, D.L. and Fernhall, B. (2011). Advanced cardiovascular exercise physiology. Champaign, IL: Human Kinetics.
