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Providing Energy for Muscle Contraction

Providing Energy for Muscle Contraction. Do Now. Do not look at yesterday’s notes 5 minutes to write down 5 things from last class. What is this molecule?. REVIEW. Direct Phosphorylation Phosphorylation of ADP by creatine phosphate (CP) Creatine Phosphate found in muscles

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Providing Energy for Muscle Contraction

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  1. Providing Energy for Muscle Contraction

  2. Do Now • Do not look at yesterday’s notes • 5 minutes to write down 5 things from last class

  3. What is this molecule?

  4. REVIEW • Direct Phosphorylation • Phosphorylation of ADP by creatine phosphate (CP) • Creatine Phosphate found in muscles • As ATP depletes, CP and ADP react to create ATP and Creatine • Muscles store about 5x as much CP as ATP • CP stores are quickly depleated as well (15 seconds)

  5. Review • Aerobic Respiration • At rest, during light or moderate exercise, the majority of ATP used for muscle contraction comes from Aerobic Respiration • 95% • Occurs in mitochondria of the cell • Glucose is broken down to CO2 and water • Energy released from broken bonds are captured in ATP molecules • What happens to the CO2? • 32 ATP per 1 glucose • Slow and requires continuous oxygen and fuel

  6. Review • Anaerobic glycolysis • Does not require oxygen • Occurs in cytosol • Glucose broken down to pyruvic acid and small amounts of energy are captured in ATP bonds • 2 ATP per 1 glucose • If enough oxygen is present, pyruvic acid enters mitochondria and follows aerobic pathway • When exercise becomes intense, pyruvic acid turns to lactic acid and process is referred to as anaerobic glycolysis

  7. Muscle Fatigue and Oxygen Deficit • Muscle fatigue – when muscles are exercised strenuously for a long time • Unable to contract even though it is being stimulated • Contractions will weaken until they are no longer possible • Muscle fatigue due to oxygen deficit • Not able to keep up with oxygen demand • Muscles lack oxygen, lactic acid accumulates

  8. Muscle Fatigue • Very rare • Most stop or slow activity so true muscle fatigue is not reached • Some marathon runners collapse due to fatigue and their muscles can no longer properly function

  9. Oxygen Deficiency • Just like any bank loan or credit card, when we get into the “negative” must pay back the oxygen stores • This is why individuals breathe rapidly and deeply to supply more oxygen • The ultimate goal is to have enough oxygen to make ATP and CP reserves

  10. Muscle Nerve Supply • Some aspects of muscle activity are not controlled, as in muscle tone • Some fibers are unconsciously firm and ready to contract • If nerve supply is destroyed, the muscle can no longer be stimulated and becomes paralyzed • Muscle begins to atrophy • Atrophy? • Hypertrophy?

  11. Creatine • Naturally occurring in the body • Kidneys, liver and pancreas • Ingested in meat and fish • Very important for energy metabolism • With Creatine supplementation, CP depletion is delayed and performance is enhanced

  12. Positive Effects of Creatine • Increased resynthesis of ATP • Increased intensity in a workout • Lactic acid buffer • Prolonging max effort and improving exercise recovery • Decreases total cholesterol and improves HDL to LDL ratio • May reduce cramps

  13. Negative Effects of Creatine • Weight gain • Due to increase in total body water • GI disturbances • Renal dysfunction • Kidney failure

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