Providing Energy for Contraction

Aerobic v. Anaerobic Respiration

Lactic Acid Fermentation Without an adequate supply of oxygen, glycolysis is the primary source of ATP production. In order for glycolysis to continue, NADH must be oxidized back to NAD + In our cells, this is accomplished by lactic acid fermentation

The Cori Cycle

Muscle Fatigue Physiological decline in maximal force or power capability of muscle contraction. – Mechanisms that cause fatigue can vary and are specific to the task being performed: Reduced ATP supply Levels of hydrogen (H + ) and calcium (Ca 2+ ) Different from psychological inability. Complete absence of ATP prevents muscle relaxation – Rigor mortis – Writer’s cramp

Lactic Acid – Friend or Foe? A side effect of high lactate (L.A.) levels is an increase in acidity of muscle cells, which slows the process of glycolysis The build up of lactic acid results in a burning sensation, however scientists believe this is a natural defense mechanisms to prevent damage during extreme exertion. Body is forced to slow down, O 2 supplies are restored, lactate reverts to pyruvate and aerobic respiration can proceed.