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Lecture 5

KINE 1020-Week 3- Lecture 5 and 6

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Kinesiology & Health Science
KINE 1020
Angelo Belcastro

Lecture 5 Jan1612 Actin Myosin Contractile Protein Interactions y Myosin and Actin produce force source of energy ATP is needed for the reaction Myosin ATPase hydrolyzes it breaks down and mechanical energy Em is released to cause the reaction the excess becomes heat energy Eh y ADP with creatine kinase regenerates to produce ATP for this reaction to continue Fatigue with heavy exercise associated with 1 When levels of inorganic phosphate Pi increase it slows down the rate at which inorganic phosphate comes off the actin myosin reactiony When the reaction is used Pi comes off of the AM reaction which is an important step for the detachment of AM reaction yTherefore the cycle cant reproduce as quickly and there is less force produced 2 Increasing hydrogen ion levels the pH will decrease become more acidicy The more ATP the more acidic the muscle pH will be ex Heavy exercise y Myosin ATPase activity is reduced at lower pH therefore less force produced 3 Loss of contractile proteinson the sarcomere itselfy 60 reduction in each of myofibrillar proteins troponinI and tropomyosin which affect the thin filaments therefore cannot perform their normal functions 4 Loss of cytoskeletal structural proteins y Alpha actinin zline and desmin myofibril linking protein y Slows down the force transmission 5 Cause Myofibril protein losses a result of increased protease activity an enzyme that breaks up proteins calcium activated neutral protease calpain CANP1 CANP2 CAPN2S1 Activity in Skeletal Muscle Influence of Heavy Exercise y Heavy exercisemore protease activity Metabolic Supply 3 systems and Accumulation Fatigue with heavy exercise associated with 1 Phosphagen Sources immediate supplier of ATP a Requires phosphocreatine PCr to take ADP and make ATP b With heavy exercise there is a significant depletion 802 Anaerobic Glycolysis providing energy wo oxygen y Glycogen coming in the anaerobic side the more glycogen the more anaerobic exercise you can use y Pyruvate last element in glycolysis goes to lactate y Main characteristic Glycogen coming in lactate going out
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