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Peripheral Fatigue

Neuromuscular Junction: With neuromuscular junction there is a breakdown of ACh in getting to the motor end plate, thus the action potential does not reach the motor end plate. Therefore, NO muscle contraction will occur.
Two sites in muscle: At one site, the H+ ions interfere with calcium ions from binding to troponin. The interference PREVENTS the configuration shift of tropomyosin to reveal the active bindings sites. In the other site, the increase in acidosis (from the H+ ion accumulation) will denature (i.e., breakdown or unfold) the enzyme ATPase, inhibiting the splitting of ATP to ADP and Pi and energy. Remember, the H+ accumulation is coming from the hydrolysis of ATP during the exercise bout. The H+ comes from the water molecule (H2O).
Special Note on Fatigue:
There are actually TWO TYPES of fatigue. CENTRAL fatigue is the signalling message from the brain to the neuromuscular junction. PERIPHERAL FATIGUE is the signally message from the neuromuscuscular junction to muscle and within the muscle. In class, we focus on peripheral fatigue.