Metabolic response

Metabolic response

1. Muscle cells use 3 major systems for ATP re-synthesis

   • Immediate (0-20 s): PCr-ATP system (Anaerobic)
   • Short term (4-120 s): Glycolytic system (Anaerobic)
     • Glycolytic system backs up ATP-PCr system since Oxidative system is slow to accelerate
     • Oxidative system is used to regenerate substrates after exercise (EPOC)
       • Excess Postexercise Oxygen Consumption
   • Long term: Oxidative system (Aerobic)
     • Creatine kinase (CK) delays the rise in ADP and slows the Oxidative system
     • relies on mitochondria
       • consume: O2, simple molecules, ADP and Pi
         • uses glucose, amino acids and fatty acids for ATP synthesis
       • produce: CO2, H2O, ATP
       • Oxidative phosphorylation (ADP + Pi => ATP +H20) is driven by H+ gradient over the internal mitochondrial membrane

2. Glycolysis is the process of glucose metabolism to pyruvate

   • Lactate is produced if pyruvate and NADH cannot be metabolized by the Oxidative system
     • Lactate diffuses into blood via lactate transporters (passive process)

3. Cori cycle between liver and muscles Exchange of glucose and lactate

   • Liver converts lactate to glucose and releases it into blood
     • Liver controls blood glucose levels at rest and during exercise
       • consumes lactate and amino acids to produce glucose (gluconeogenesis)
       • hydrolyses its glycogen