HES 319 Lecture Notes - Myosin, Motor Unit, Glycolysis
Document Summary
Things that are very different among/between motor units within a muscle. Fast fatigable motor unit has rapid decline in force. Motor units with long contraction times (s) exert low tetanic forces. Motor units with fast contraction times (fr and ff) exert tetanic forces that range from low to high. Difference in tetanic force among motor units is mainly due to variation in innervation number. A fast-twitch motor unit, therefore, does not necessarily correspond to a motor unit that can exert a large force. As intensity increases, fr motor units are recruited. Maximal activities (e. g. , vertical jump) recruit ff motor units. Muscle fibers can be classified with several techniques. Histochemical staining for myosin atpase: types i (slow), iia (intermediate), iib (fast) (iix or iid) Histochemical assays for oxidative and glycolytic enyzmes: types so (slow oxidative), fog (fast oxidative glycolytic), fg (fast glycolytic) Molecular measurable of myosin heavy chain content: types mhc-i, mhc-iia,
