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

What is the function of sweat during heat regulation?

1. To provide moisture to the skin

2. To facilitate the evaporation of heat from the body

3. To trap heat and maintain warmth

4. To cool the blood flow through the veins

The correct answer is: To facilitate the evaporation of heat from the body

The function of sweat during heat regulation primarily revolves around its ability to facilitate the evaporation of heat from the body. When the body becomes overheated, such as during exercise or in hot environments, sweat glands produce sweat, which is primarily composed of water. As the sweat evaporates from the skin's surface, it absorbs heat from the body, leading to a cooling effect. This process is crucial for maintaining optimal body temperature and preventing overheating. The other options do not accurately represent the primary role of sweat in heat regulation. While moisture on the skin can feel refreshing, it does not serve as a primary function for temperature control. Trapping heat and maintaining warmth is contrary to the purpose of sweating, which is to cool the body down. Cooling blood flow through the veins may happen as a secondary effect of sweating, but it is not the direct function of the sweat itself. Thus, the focus remains on how the evaporation of sweat effectively removes heat and helps regulate body temperature.