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Student%20Lecture%204%20%28Metabolism%29 - Lecture 4...

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Unformatted text preview: Lecture 4 Metabolism Metabolism Thursday 1­21­10 Outline Outline Extra Credit – – – – – Friday, January 29 Dr. Jesse Witt Assistant Professor Psychological Sciences Performance affects perception: Evidence form size, shape, and speed judgments – LAMB 108, 1:30 P.M. Questions Grant Assignment #1 Lecture Muscle Metabolism Review Review Why is oxygen a critical in ATP Why production? production? Glycolysis Krebs Cycle ETC Measurement of oxygen Measurement of oxygen consumption (VO2) is an index of _______________. *Measurement of VO2 *Measurement Open Spirometry or “metabolic cart” Vo2 = _____________ ­ ____________ What happens to VO2 when going What happens to VO from rest to exercise? Oxygen Deficit Oxygen Oxygen uptake increases rapidly ____________ – Reaches steady state within ______ minutes After steady state is reached, ATP requirement is met through aerobic ATP production – Lag in oxygen uptake at the beginning of exercise – Suggests anaerobic pathways contribute to total ATP production Fig 4.1 Are there differences in the O2 Are there differences in the O deficit between sedentary and trained individuals? Differences in O2 Deficit Between Differences Sedentary & Trained Subjects Sedentary Trained subjects have ____________ compared to sedentary subjects. Mechanism – Trained have enhanced aerobic bioenergetics Fig 4.2 What happens to VO2 exercise What happens to VO stops? Recovery From Exercise VO2 Recovery Response Response _________ VO2 for several minutes immediately following exercise ____________ or _______________ (EPOC) Comprised of a ____ and _____ Portion 20% of O2 debt is used to convert lactic acid to glucose (gluconeogenesis) Fig 4.3 O2 Debt “Rapid” portion of O2 debt – _________________ – Replacing muscle and blood O2 stores “Slow” portion of O2 debt – Elevated _______ and _______, ↑ energy need – Elevated ___________, ↑ metabolic rate – Elevated _________ & ________, ↑ metabolic rate Fig 4.5 Tuesday afternoon I went on a 60 minute Tuesday afternoon I went on a 60 minute run and maintained the same pace throughout the duration of the run. Was the oxygen consumption required to perform this activity the same at the beginning and end of my run? Hint: the temperature was above 90 degrees Steady State Exercise Steady Prolonged exercise in a hot/humid environment or at high intensity – Steady state not achieved – __________________ __________________ ____________ – WHY???? Fig 4.6 Incremental Exercise Incremental Oxygen uptake increases linearly until ________ is reached Physiological factors influencing VO2max – No further increase in VO2 with increasing work rate – _____________________ _____________________ _____________________ _____________ – _____________________ _____________________ _______________ Fig 4.7 Is VO2maX alone predictive of Is VO exercise performance? Lactate Threshold Lactate The point at which blood lactic acid suddenly rises during incremental exercise Also called – _______________ – __________________ __________________ ____________ Fig 4.8 Mechanisms for lactate threshold Mechanisms Low muscle oxygen Accelerated glycolysis Recruitment of fast­ twitch muscle fibers Reduced rate of lactate removal from the blood Fig 4.10 Other Mechanisms for the Lactate Threshold Lactate _______________________ _______________________ _______________________ ___________ – Excess NADH in sarcoplasm favors conversion of pyruvic acid to lactic acid _______________________ _________________ – Enzyme that converts pyruvic acid to lactic acid – LDH in fast­twitch fibers favors formation of lactic acid Fig 4.9 How is substrate utilization How is substrate utilization determined during exercise? Respiratory Exchange Ratio Respiratory RER or R VCO2/VO2 Fat (palmitic acid) = C16H32O2 Glucose = C6H12O6 – C16H32O2 + 23O2 → 16CO2 + 16H2O + ?ATP – R = ________________________________ – C6H12O6 + 6O2 → 6CO2 + 6H2O + ?ATP – R = ____________________________ Contribution of _______ under normal exercising conditions is _________. Breakdown of RER Breakdown R 0.70 0.75 0.80 0.85 0.90 0.95 1.00 % Fat 100 83 67 50 33 17 0 % Carbohydrate 0 17 33 50 67 83 100 Table 4.1 What is the primary substrate used What is the primary substrate used during 1) low and 2) high intensity exercise? Exercise Intensity and Substrate Utilization Utilization Low­intensity exercise (<30% VO2max) – _________________ High­intensity exercise (>70% VO2max) “________” concept – Describes the shift from fat to CHO metabolism as exercise intensity increases – _________________ Fig 4.11 Mechanisms underlying cross-over to carbohydrate utilization during high intensity exercises high Recruitment of _______muscle fibers Increased ______________ Increases _________ production which inturn inhibits lipolysis – Few mitochondria and lipolytic enzymes What is the optimal exercise What is the optimal exercise intensity if an individual wants to loss excess body fat? What happens to substrate utilization What happens to substrate utilization when the duration of exercise increases? Exercise Duration and Substrate Utilization Substrate During prolonged exercise, there is a shift from ____________________ ________________ Increased rate of _________ – Breakdown of triglycerides into glycerol and free fatty acids (FFA) – Stimulated by rising blood levels of _________ Fig 4.14 Where are carbohydrates and fats Where are carbohydrates and fats stored? Sources of Fuel During Exercise Sources Carbohydrate Fat – – – – ____________ (from liver glycogenolysis) Muscle _______ ____________ (from adipose tissue lipolysis) Intramuscular __________ Protein – Only a small contribution to total energy production (only ~2%) May increase to 5­15% late in prolonged exercise _____________ – Gluconeogenesis via the Cori cycle Carbohydrate Carbohydrate Storage Sites Liver glycogen Blood glucose Muscle glycogen Mixed Diet 240kcal 40kcal 1,400kcal Fat Storage Sites Adipocytes Muscle Mixed Diet 107,800kcal 3,850 kcal Table 4.2 High CHO Low CHO Diet Diet 360 kcal 120kcal 40kcal 2,400kcal 40kcal 1,200kcal Effect of Exercise Intensity on Muscle Fuel Source Muscle Fig 4.15 *Effects of Exercise Intensity on Liver Glucose Output ACSM’s Advanced Exercise Physiology What happens to the relative What happens to the relative contribution of plasma and muscle sources of CHO and fat as exercise duration increases? Effect of Exercise Duration on Muscle Fuel Source Muscle Fig 4.16 *Effects of Exercise Duration on Liver Glucose Output Liver ACSM’s Advanced Exercise Physiology The Cori Cycle: The Lactate As a Fuel Source Fig 4.17 *Glucose Transport During Exercise Exercise During exercise glucose uptake into the myocyte is regulated by _____. Potential regulators – – – _____ AMPK MAPK Chronic exercise training increases _____ concentrations ACSM’s Advanced Exercise Physiology *Resynthesis of Muscle Glycogen Jonas Bergstrom and Eric Jonas Bergstrom and Eric Hultman 1967 Nature Demonstrated that the depletion of muscle glycogen during exercise can lead ____________________ ____________________ ______________ ACSM’s Advanced Exercise Physiology ...
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