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Bioen 599 F, Autumn 2000 Bioengineering Principles of Physiology |
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Lecture Material and Notes Week 8, Lecture 23: Motor
units Lecture theme and outline: · A motor unit is one nerve and the muscle cells it synapses with. · Skeletal muscle cells not active without signaling from nerves, except in pathology. · Ratio of # of muscle cells per nerve varies greatly. · All cells in one motor unit are functionally similar - importance will be clearer in week 10 and 11. · Properties of motor units: - threshold for activation of motor nerve - speed of shortening of muscle cells - fatiguability of muscle cells - rates of electrical depolarization when active. · Recruitment: each motor unit has a relatively fixed threshold. · Recruitment order by size of nerve cell body. Reading Patton et al., eds. Textbook of Physiology - Ch. 23 - Handout. |
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Contact the instructor at: kushmeri@u.washington.edu
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