The body must maintain an internal temperature of 37 degrees as this is the optimum temperature for body’s enzymes. When the body gets too hot the body responds in multiple ways: • The body releases sweat from sweat glands in the skin. The sweat then evaporates off the surface of the skin, removing heat energy • Blood vessels leading to the skin dilate (widen), which means more blood gets to the skin’s surface. More heat is then lost from the blood. When the body gets cold: • The body shivers, which is the muscles rapidly contracting. This contraction requires energy from respiration, which also produces heat. • The blood vessels leading to the skin constrict (become narrower), which means less blood reaches the skin surface, and less heat is lost.