Histotoxic hypoxia results from

Histotoxic hypoxia results from

• A. An Inability of the Heart to Pump Blood.
• B. An interference with the use of O2 by body tissues.
• C. Low ambient oxygen concentration.
• D. Excess carbon dioxide in blood.

Answer: (B)

Histotoxic hypoxia happens when oxygen is delivered to the tissues, but the cells can’t use it because a toxin or poison interferes with cellular respiration. The classic example is cyanide blocking the mitochondrial enzymes needed for oxidative phosphorylation, so even with normal or adequate oxygen in the blood, the tissues can’t extract and use it. Because the cells can’t burn oxygen, metabolism shifts toward anaerobic pathways, producing lactic acid and leading to tissue hypoxia despite normal oxygen delivery. This differs from other types of hypoxia: a heart that can’t pump blood effectively causes circulatory (or stagnant) hypoxia, low ambient oxygen concentration causes hypoxic hypoxia, and excess carbon dioxide affects ventilation and gas exchange rather than blocking the cells’ ability to use oxygen.

Histotoxic hypoxia happens when oxygen is delivered to the tissues, but the cells can’t use it because a toxin or poison interferes with cellular respiration. The classic example is cyanide blocking the mitochondrial enzymes needed for oxidative phosphorylation, so even with normal or adequate oxygen in the blood, the tissues can’t extract and use it. Because the cells can’t burn oxygen, metabolism shifts toward anaerobic pathways, producing lactic acid and leading to tissue hypoxia despite normal oxygen delivery.

This differs from other types of hypoxia: a heart that can’t pump blood effectively causes circulatory (or stagnant) hypoxia, low ambient oxygen concentration causes hypoxic hypoxia, and excess carbon dioxide affects ventilation and gas exchange rather than blocking the cells’ ability to use oxygen.