Energy for Muscle Contraction PDF

NOTES #3 – ENERGY FOR MUSCLE CONTRACTION  ENERGY FOR MUSCLE CONTRACTION Initially, muscles used stored ATP for energy ATP – adenosine triphosphate Bonds of ATP are broken to release energy Only 4-6 seconds worth of ATP is stored by muscles After this initial time, other pathways must be uti...

NOTES #3 – ENERGY FOR MUSCLE CONTRACTION  ENERGY FOR MUSCLE CONTRACTION Initially, muscles used stored ATP for energy ATP – adenosine triphosphate Bonds of ATP are broken to release energy Only 4-6 seconds worth of ATP is stored by muscles After this initial time, other pathways must be utilized to produce ATP ENERGY FOR MUSCLE CONTRACTION Direct phosphorylation Muscle cells contain creatine phosphate (CP) CP is a high-energy molecule After ATP is depleted, ADP is left Adenosine Diphosphate CP transfers a phosphate group to ADP, to regenerate ATP CP supplies are exhausted in about 20 seconds Figure 6.10a ENERGY FOR MUSCLE CONTRACTION Aerobic Respiration Series of metabolic pathways that occur in the mitochondria Mitochondria – turns sugar into energy Glucose is broken down to carbon dioxide and water, releasing energy This is a slower reaction that requires continuous oxygen Figure 6.10b ENERGY FOR MUSCLE CONTRACTION Anaerobic glycolysis Aka anaerobic respiration Reaction that breaks down glucose without oxygen Glucose is broken down to pyruvic acid to produce some ATP Pyruvic acid is converted to lactic acid This reaction is not as efficient, but is fast Huge amounts of glucose are needed Lactic acid buildup makes muscles sore Lactic acid produces muscle fatigue Figure 6.10c MUSCLE FATIGUE AND OXYGEN DEBT ❖When a muscle is fatigued, it is unable to contract even when being stimulated ❖The common reason for muscle fatigue is oxygen debt ❖Can’t get enough oxygen to cells ❖Oxygen is required to get rid of accumulated lactic acid ❖Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less EFFECTS OF EXERCISE ON MUSCLE Results of increased muscle use 1. Increase in muscle size 2. Increase in muscle strength 3. Increase in muscle efficiency 4. Muscle becomes more fatigue resistant