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Chapter 25

Chapter 25. Integrative Physiology III: Exercise. About this Chapter. Overview of how major systems are involved in the metabolism for skeletal muscle contraction How the extreme activities of exercise disrupt homeostasis

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Chapter 25

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  1. Chapter 25 Integrative Physiology III: Exercise

  2. About this Chapter • Overview of how major systems are involved in the metabolism for skeletal muscle contraction • How the extreme activities of exercise disrupt homeostasis • Focus on how the circulatory & respiratory systems integrate their responses to exercise demands • How exercise impacts health

  3. Integration of Metabolism: Review of Roles of Systems in Muscle Contraction • Reactants • Transport • Conversions • Energy produced • Contractions • Respiration • Excretion • Endocrine • Nervous

  4. Integration of Metabolism: Review of Roles of Systems in Muscle Contraction Figure 25-1: Energy metabolism in skeletal muscle

  5. Energy for Skeletal Muscle Contraction • ATP & ADP • Phosphocreatine • Aerobic paths • Anaerobic paths • (glycolytic metabolism)

  6. Sustaining Muscle contractions: ATP Sources/Time • Phosphocreatine: Short bursts at maximal effort • Anaerobic: Intermediate duration intense effort • Aerobic: Long duration at reduced effort Figure 25-2: Speed of ATP production compared with ability to sustain maximal muscle activity

  7. Hormonal regulation of Energy Source for ATP Production • (Huge body reserves – glucose 2000 & FAAs 70,000 Kcal) • Exercise intensity • Glucose • Fatty acids

  8. Hormonal regulation of Energy Source for ATP Production • Metabolic Shifts • Glucagon • Cortisol • Epinep./NE • GH • (insulin)

  9. Hormonal regulation of Energy Source for ATP Production Figure 25-3: Use of carbohydrates and fats with increasing exercise

  10. Oxygen Consumption: Factors Sustaining or Limiting Exercise • O2 consumption:: to  exercise (measure w/Vo2 max) • Limiting factors: • O2 – cell availability, (O2 deficit) • O2 – transport to: mitochondria, to cell, to blood, or to lung

  11. Oxygen Consumption: Factors Sustaining or Limiting Exercise Figure 25-4: Changes in oxygen consumption during and after exercise

  12. Respiratory Ventilation: Exercise Induced hyperventilation • Feed forward Reflex: CNS • Feedback reflexes: • Motor sensors • Joint movement • Muscle contraction • Chemo sensors • O2 & CO2 levels • Synchronized w/ cardiac output • Plasma: [O2], [CO2] & [ pH]

  13. Respiratory Ventilation: Exercise Induced hyperventilation Figure 25-5: Changes in ventilation with submaximal exercise

  14. Respiratory Ventilation: Exercise Induced hyperventilation Figure 25-6: Changes in blood gas, partial pressures, and arterial pH with exercise

  15. Cardiovascular Response to Exercise • Cardiac output •  5 to 35 L/min • Rate  2-3 X • Blood distribution •  muscles to 88% of all blood •  other tissues (except brain)

  16. Cardiovascular Response to Exercise Figure 25-7: Distribution of cardiac output at rest and during exercise

  17. Homeostatic Balancing of Exercise: “Controlled Disruption” • Feed forward reflexes • Anticipate demand • Heart & lungs • Protective reflexes • Stretch damage • Temperature  • sweating •  peripheral • blood flow • redistribution • Blood pressure  constant

  18. Homeostatic Balancing of Exercise: “Controlled Disruption” Figure 25-8: Peripheral resistance and arterial blood pressure during exercise

  19. Health Advantages of Regular Exercise: Quality of Life •  Cardiovascular disease risks: heart attack, stroke, high BP •  blood pressure •  LDL & triglycerides •  HDL  risks for diabetes • [blood [glucose] •  obesity •  stress association •  immune function • (to a point)

  20. Health Advantages of Regular Exercise: Quality of Life Figure 25-9b: The effect of exercise on glucose tolerance and insulin secretion

  21. Health Advantages of Regular Exercise: Quality of Life Figure 25-10: Immune function and exercise

  22. Summary • Exercise challenges a range of many systems involved in metabolism to produce maximal energy from various nutrient sources • Phosphocreatine most quickly produces ATP for muscle contraction while anaerobic glycolysis is intermediate • Aerobic ATP production is needed for endurance exercise

  23. Summary • Ventilation and cardiac rate and output undergo huge changes which are anticipated by feed forward reflexes and protected by other reflexes to keep BP and temperature in homeostatic • Exercise reduces risk factors in some most common health problems: heart disease, obesity , diabetes, and stress

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