PSIO 201 5th Edition Lecture 21 Outline of Last Lecture Muscle Mechanics Outline of Current Lecture I Muscle Energetics II ATP III Creatine Phosphate Pool IV Fatigue V Cori Cycle Current Lecture The Immediate source of energy to support development of tension ATP 1 hydrolysis by the myosin head group fuels tension generation 2 Hydrolysis by the Ca pump of the SR supports relaxation Where does ATP come from 1 Cell pool of ATP ATP is not stored only keeps enough to support 2 seconds of maximal force 2 Creatine Phosphate CP pool stores high energy phosphate CP pool has enough energy phosphate to last 15 seconds of maximal contraction Creatine Phosphate Pool 1 After meal ATP C ADP CP 2 During Exercise ADP CP ATP C Creatine These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Is a small amino acid like molecule that is synthesized in the liver kidney and pancreas and transported to muscle fibers In a relaxed muscle fiber creatine is 3 6 more plentiful than ATP Where does the ATP come from 3 Glycogen storage form of glycose used anaerobically occurs rapidly and in the cytoplasm 2 minutes of contraction 4 Glycogen fat and protein used aerobically occurs slowly and in mitochondria can support 40 min to several hours of contraction intensity dependent Fatigue Cost of Peak Activity Progressive increase in the effort needed to maintain desired force remain force in repetitive or contained contractions Can be psychological muscle nervous fatigue Fatigue Problem Causes 1 Glycogen depletion 2 Lactic and Buildup from anaerobic glycolysis 3 Phosphate build up from creatine phosphate metabolism Cori Cycle Muscle Lactic acid Liver Glucose Elevated O2 consumption after exercise 1 2 3 4 Lactic acid conversion back to glycogen in the liver Cori Cycle Resynthesize creatine phosphate Replace oxygen removed from myoglobin Repair and etc
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