Practice Questions

<ul style="color: rgb(255,255,255);"><li>Statement 1 is True: Muscle fatigue is a physiological phenomenon characterized by the decline in maximal force or power production capacity of a muscle during sustained activity. Repeated activation exhausts energy substrates (like ATP and phosphocreatine) and alters ionic balance, leading to a temporary inability to maintain the required force.</li><li>Statement 2 is False: The assertion incorrectly attributes lactic acid accumulation to aerobic breakdown. Lactic acid (or more accurately, lactate and hydrogen ions) is a byproduct of anaerobic glycolysis (breakdown of glycogen in the absence of sufficient oxygen), not aerobic respiration.</li><li>Understanding Muscle Fatigue Mechanisms: <ul style="color: rgb(255,255,255);"><li>Anaerobic Glycolysis: When oxygen demand exceeds supply during intense exercise, cells switch to anaerobic metabolism. This process produces lactate and H+ ions, leading to metabolic acidosis, which contributes to fatigue.</li><li>Aerobic Breakdown: Aerobic respiration (using oxygen) breaks down glycogen into CO2, H2O, and ATP. This is the efficient, primary energy system for sustained, lower-intensity activity and does not result in lactic acid accumulation.</li><li>Ionic Imbalance: High-intensity exercise causes potassium ion (K+) accumulation outside muscle cells and calcium ion (Ca2+) handling issues within the sarcoplasmic reticulum, which are critical factors in fatigue.</li></ul></li></ul>

Statement A is correct but B is incorrect

Statement A is incorrect but Statement B is correct

Repeated activation of muscles can lead to fatigue.

Lactic acid accumulation by aerobic breakdown of glycogen causes muscle fatigue

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