Ch 6 p2

• • ATP must be continuously regenerated for contraction to continue via 3 pathways:

  1. direct phosphorylation of ADP by creatine phosphate 
  2. aerobic respiration 
  3. aerobic glycolysis and lactic acid formation 
• DIRECT Phosphorylation

  • Muscle cells store 5x as much creatine phosphate as ATP 
  • Once ATP is depleted: ADP interacts with the creatine phosphate from CP to ADP = ATP regeneration 
  • CP supplies exhausted in <15s
• AEROBIC RESPIRATION

  • Slow, requires continuous O2 and nutrients 
  • Happens at rest & during light- moderate exercise
  • 95% ATP obtained this way 
  • Series of metabolic pathways that use O2
  • Takes place mitochondria
  • Glucose —> CO2 + h20, ATP released 
• ANAEROBIC GLYCOSIS/ LACTIC ACID FORMATION

  • Glycolysis: reaction that breaks down glucose without O2 in the cytosol
  • Not as efficient, but fast

  -Huge amounts of glucose are needed

  -lactic acid produce muscle fatigue 

  • When muscle activity intense OR O2 & C6H12O6 delivery inadequate
  • 1.Uses huge amounts of glucose for small ATP amount
  • lactic acid promotes muscle soreness
• • Muscle tone: continuous partial contractions, necessary for healthy firm muscle
  • Flaccid- muscle no long stimulated due to nerve supply to muscle destroyed = muscle loses its tone = soft, flabby
  • Atrophy- muscle wastes away = flaccid paralysis 
  • Tetanus- increases muscle tone until muscle no longer controllable= spastic pralysis,