Muscle Stroke: A Case Study

Muscle contractions are due to the sliding-filament model where the filaments slide longitudinally past each other producing an overlap between thin and thick filaments. The sliding filaments rely on the reaction between actin and myosin. Calcium ions bind to the troponin complex on the actin filaments and cause the tropomyosin to change the orientation of the actin filament to expose the myosin head binding sites on the actin filament. Glycolysis and aerobic respiration generate adenosine triphosphate (ATP) to sustain muscle contraction. Glycolysis is the decomposition of glucose and releases energy due to enzymes (Aryal, 2015). Aerobic respiration is the production of cellular energy in the mitochondria (Roisen, 2008). The head of the myosin filament binds to the actin filament forming a cross-bridge. The myosin pulls the actin towards the centre of the sarcomere creating a power stroke. A specific chemical reaction needs to occur in order for the myosin to acquire the sufficient energy to pull the actin filament. A fact from Chemistry gives a greater understanding of the chemical reactions that occur during a power stroke thus giving a greater understanding of the filament interaction from a molecular perspective.
Hydrolysis of ATP is needed to release energy, thus the hydrolysis reaction that occurs is an exothermic reaction (Crofts, 1996). Hydrolysis is the reaction with water whereby a compound is decomposed (Kim,