Final answer:
When a thermal mask cools, it causes sweat production to decrease and blood vessels to constrict in a process called vasoconstriction, helping to conserve body heat and maintain a balanced internal body temperature.
Step-by-step explanation:
When a thermal mask cools on the skin, it can lead to a decrease in skin temperature, prompting several physiological reactions. First, sweat production by the sweat glands will decrease since there is less need to evaporate sweat for cooling. Additionally, the blood vessels within the skin constrict, a process known as vasoconstriction, to reduce blood flow near the surface of the skin and minimize heat loss.
This constriction helps to conserve body heat, maintaining internal body temperature in a balanced state. The skin may appear paler as the blood vessels narrow, which reduces the amount of warm blood reaching the skin's surface. This response is part of a larger system of temperature regulation managed by the hypothalamus in the brain, ensuring the body remains within an optimal temperature range.