The Sources of Energy for Muscle Contraction

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Student Number 39331040 Leroux van der Hoven FIS3703 Discuss the sources of energy for muscle contraction Sources of energy for muscle contraction Muscle contraction is dependent on energy supplied by ATP. The majority of this energy is needed to actuate the walk-along mechanism by which the cross-bridges drag the actin filaments, but some energy is also needed for (1) propelling C ions into the sarcoplasmic reticulum from the sarcoplasm after the contraction is over and (2) propelling sodium and potassium ions through the muscle fiber membrane to keep suitable ionic environment for conduction of muscle fiber action potentials The ATP concentration in the muscle fiber is enough to maintain full contraction up to 2 seconds.…show more content…
(2) The tempo of ATP formation by the glycolytic process is 250% quicker than ATP formation in reply to cellular foodstuffs reacting with oxygen. However, glycolysis loses its capacity to continue maximum muscle contraction after a minute due to the fact that many end products of glycolysis build up in the muscle cells. Yet another source of energy is oxidative metabolism. This involves oxygen reacting with end products of glycolysis and with many other cellular foodstuffs to free ATP. More than 95% of all energy required by muscles for continued, long term contraction is obtained from this source. The foodstuffs consumed include carbohydrates, fats and protein. For particularly long-term maximal muscle activity (for several hours) by far the most energy being used comes from fats but for shorter periods (2 – 4 hours) as much as 50% of the energy can come from stored carbohydrates. Efficiency of muscle contraction The effectiveness of an engine or a motor is determined by taking the percentage of energy input that is converted into work instead of heat. The percentage of the input to muscle that can be converted into work is always less than 25% with the rest becoming heat. The explanation for this low efficiency is that roughly 50% of the
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