Which of the following organs or tissues can survive the longest without oxygen?

• A. Muscle
• B. Liver
• C. Heart
• D. Kidneys

Answer: (A)

Tissue tolerance to hypoxia depends on how much oxygen a tissue needs and how it can generate energy when oxygen is scarce. Skeletal muscle at rest uses relatively less oxygen than the heart or brain and has stored glycogen, so it can switch to anaerobic glycolysis and sustain ATP production longer during oxygen shortages. In contrast, the brain and heart are highly sensitive to lack of oxygen and begin to suffer damage quickly, while the kidneys are also quite vulnerable due to their energy demands. The liver is somewhat resilient because of glycogen stores and dual blood supply, but it doesn’t outlast skeletal muscle in this context. So, skeletal muscle can survive the longest without oxygen.