Cellular hypoxia refers to…

• A. Cells not receiving oxygen
• B. Cells receiving too much oxygen
• C. Lactic acid buildup
• D. Adequate perfusion

Answer: (A)

Cellular hypoxia occurs when cells don’t get enough oxygen to meet their metabolic needs. Oxygen is essential for efficient ATP production via oxidative phosphorylation in mitochondria; without sufficient oxygen, energy generation drops and cells rely more on anaerobic glycolysis, which can lead to lactate buildup as a byproduct. This condition is about inadequate oxygen delivery or utilization at the cellular level, not about having too much oxygen. The other ideas aren’t the definition: too much oxygen describes hyperoxia, lactate buildup is a consequence of hypoxia rather than the definition itself, and adequate perfusion means oxygen delivery is sufficient, not hypoxic.