B7

WHEN YOU'RE TOO HOT:

Blood vessels close to the skin's surface get bigger in diameter - this is called vasodilation. This allows more blood to get to the surface of the skin so the warm blood loses more of its heat to the surroundings

Your sweat glands produce more sweat - when the water in the swear evaporates, heat is used which cools the body. If you sweat alot e.g. when exercising, you will lose water and may become dehydrated. If you're dehydrated you'll produce less sweat which means your core body temp. will increase

WHEN YOU'RE TOO COLD:

Blood vessels close to the skin's surface get smaller in diameter - this is called vasoconstriction. This means that less blood gets the surface of the skin which stops the blood losing as much heat to the surroundings

You shiver - your muscles contract rapidly which increases the rate of respiration and warms the tissue surrounding the muslces