Anaemic hypoxia is described as being caused by ...

• A. Caused by a lack of oxygen in ambient air
• B. Caused by an over abundance of carbon monoxide in the blood
• C. Caused by dehydration
• D. Caused by excessive carbon dioxide in the blood

Answer: (B)

Anemic hypoxia happens when the blood’s ability to carry oxygen is reduced, so tissues don’t get enough oxygen even if the air and lungs are delivering it normally. A common cause is carbon monoxide in the blood, because CO binds strongly to hemoglobin to form carboxyhemoglobin. This not only blocks oxygen from binding but also makes the remaining hemoglobin hold onto oxygen more tightly, reducing how much is delivered to tissues. That’s why this type of hypoxia resembles anemia—there’s less usable oxygen circulating despite adequate oxygen pressure in the lungs.

The other scenarios don’t fit anemic hypoxia: lacking oxygen in the air causes hypoxic hypoxia; dehydration lowers blood volume rather than carrying capacity; and excessive carbon dioxide causes hypercapnic hypoxia from ventilation issues, not a reduced oxygen-carrying capacity.