Temperature Regulation Quiz

See Classifications of Body Temperature. Option E is correct. The core body temperature, meaning the temperature of the deep organs, is tightly regulated around 37°C, and the typical normal range for an adult is about 36.5 to 37.5°C (often written 37°C ± 1°C). It is kept steady by a negative feedback loop (a system that detects a change and then acts to reverse it). Temperature sensors in the skin and in the hypothalamic preoptic area (the part of the brain that measures the blood temperature directly) send information to the hypothalamus, which then triggers responses that cool the body when it is too hot, such as sweating and skin vasodilation, or warm it when it is too cold, such as shivering and vasoconstriction. Enzymes, the proteins that speed up the body's chemical reactions, work best in this narrow range, which is why it is so tightly controlled. The exact value varies with the person, the time of day and where the temperature is measured, so the range is a guide. Below 35°C is hypothermia, and above 38°C is a high temperature.

• Normal range: about 36.5 to 37.5°C in an adult.
• Set point: core body temperature is regulated around 37°C.
• Control: a negative feedback loop through the hypothalamus keeps it steady.