An increase in body temperature above the normal range, often in response to infection or illness, is called what?

• A. Heat exhaustion
• B. Fever
• C. Bronchodilation
• D. Inflammation

Answer: (B)

Fever is a regulated rise in body temperature in response to infection or illness. It happens when pyrogens—substances from pathogens or produced by immune cells—signal the hypothalamus to raise the body's thermostat, typically via prostaglandin E2. To reach the new, higher set point, the body generates heat through shivering and reduces heat loss, which is why you might feel cold and chivery at first. As the pyrogens clear and the set point returns to normal, the body cools down through sweating and vasodilation.

This helps the immune system work more effectively and can slow pathogen growth. Other terms describe different processes: heat exhaustion results from environmental heat and dehydration rather than a regulated infection-related set point; bronchodilation is widening of the airways; inflammation is a local tissue response with redness, heat, swelling, and pain, not a generalized fever.