Describe the physiology of skeletal muscle cell contraction.
This question required a description of excitation- contraction coupling. Marks were gained for a brief outline of the structure of a sarcomere and how it facilitates shortening. An explanation of membrane processes, receptor interactions and the contraction processes was required. Mention of the role of ATP was also required and marks were gained for commenting on the mechanism of return to the relaxed state.
Most candidates wrote extensively on the nerve action potential and neuromuscular junction transmission, with minimal reference to events occurring within the skeletal muscle cell membrane. They could not gain marks for this. Few candidates demonstrated knowledge of the ATP dependent walk along processes of myosin heads during contraction.
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Calderón, Juan C., Pura Bolaños, and Carlo Caputo. "The excitation–contraction coupling mechanism in skeletal muscle." Biophysical reviews 6.1 (2014): 133-160.