Lecture23-2009W - (c aerobic catabolism 2 Speed of muscle contraction/relaxation(1 myosin heavy chain isoforms b the rate of ATP hydrolysis

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1 Fiber types in vertebrate skeletal muscle c tonic fibers : slow contraction, No AP e.g. eyeball muscle c twitch (or phasic ) fibers: (a) slow oxidative (SO, type I) fibers b contract slowly, fatigue slowly (b) fast oxidative (FO, type IIa) fibers b rapid repetitive movements, fatigue b e.g. flight muscles of migratory bird (c) fast glycolytic (FG, type IIb) fibers b very rapid contraction, white, fatigue b e.g. breast muscles of domestic fowl Mixtures of different muscle fibers Q) swimmer vs. cyclist? Energetics of muscle contraction c ATP consumption : (a) Myosin ATPase - detatchment of myosin from actin - power stroke (b) Calcium pumps c ATP regeneration during muscle activity (a) high-energy phosphatate (e.g. creatine phosphate) (b) anaerobic glycolysis
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Unformatted text preview: (c) aerobic catabolism 2 Speed of muscle contraction/relaxation (1) myosin heavy chain isoforms : b the rate of ATP hydrolysis varies (2) Sequestration of Ca2+ by Ca2+ ATPase (3) Speed of contraction: FG > FO > SO Neuronal control of muscle contraction Vertebrates Invertebrates Motor unit c Vertebrates : (a) antagonistic pairs – flexor and extensor muscles (b) excitatory - ACh (c) increasing muscle tension b no gradation in a motor unit b High-frequency AP b activating more motor units b different types of muscle fibers c Arthropods: (a) all-or-none twitch + graded (multi-synaptic terminals) (b) multi-neuronal innervation (excitatory + inhibitory)...
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This note was uploaded on 03/11/2009 for the course BIOS 342 taught by Professor Tanda during the Spring '09 term at Ohio University- Athens.

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Lecture23-2009W - (c aerobic catabolism 2 Speed of muscle contraction/relaxation(1 myosin heavy chain isoforms b the rate of ATP hydrolysis

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