Anaerobic respiration occurs in muscle tissue when oxygen is insufficient. Which condition is most directly a result?

• A. Necrosis
• B. Cramps
• C. Bleeding
• D. Swelling

Answer: (B)

When oxygen is scarce, muscle cells switch to anaerobic respiration to keep producing ATP. This pathway converts glucose to lactic acid, so lactate accumulates and lowers the intracellular pH. That acid buildup irritates and destabilizes muscle fibers, often leading to temporary, involuntary contractions or cramps. So cramps are the most direct result of relying on anaerobic metabolism in muscle.

Necrosis would require prolonged or severe oxygen deprivation and is not the immediate outcome of short-term anaerobic metabolism. Bleeding and swelling relate to injury or inflammatory processes rather than the metabolic shift to anaerobic respiration.