Question

Why does a skeletal muscle eventually fatigue with constant stimulation?

a) it creates too much oxigen

b) because it can only generated then contractions in a minute

c) because of prolonged rest periods

d) because there is a buildup of lactic acidosis

Answer 1

because there is a buildup of lactic acidosis

The skeletal muscle eventually fatigue upon constant stimulation causes the nerve fatigue and the metabolic fatigue. The metabolic fatigue occus when there is shortage of the substrate within the muscle fibers or when there is accumulation of the metabolites.The substrates which helps in muscle contractions are the ATP,creatinine phosphate and glycogen.The accumulation of the metabolites cause the muscle fatigue within the muscle fibers, that interfers with the calcium sensitivity with the actin and myosin.The metabolites includes the chlorides, potassium ,lactic acid,magnesium,reactive oxygen species, inorganic phosphate and ADP. Therefore the builiding up of the lactic acid causes the skeletal muscle fatigue upon rigrous contractions and reduces the oxygen supply into the muscle fibers to function.