OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What response occurs when body temperature rises?

1. Blood vessels constrict

2. Shivering increases

3. More sweat is produced

4. Body hairs stand on end

The correct answer is: More sweat is produced

When body temperature rises, one of the primary responses is the production of more sweat. Sweating is a crucial mechanism that helps regulate body temperature through evaporative cooling. As the body temperature increases, sweat glands become more active, releasing sweat onto the surface of the skin. As the sweat evaporates, it carries heat away from the body, which helps lower the overall temperature. This physiological response is vital during situations of heat stress, exercise, or hot environments to prevent overheating. Other responses such as blood vessels dilating (rather than constricting) can also occur, allowing for increased blood flow to the skin, which further aids in heat loss. In contrast, mechanisms like shivering, which generates heat through muscle activity, are more relevant when the body is too cold. Similarly, the standing of body hairs helps trap air for insulation in the cold but is not beneficial when trying to cool down. Hence, the increase in sweat production directly addresses thermal regulation during a rise in body temperature.