controlling body temperature

• there is a thermoregulatory centre in the brain which contains receptors that are sensitive to the temperature of the blood flowing through the brain
• body temperature is controlled via negative feedback
• antagonistic effectors oppose each other's actions
• when the body is too hot: hairs lie flat ; sweat is produced by sweat glands and evaporates from the skin, transferring energy to the environment and vasodilation happens in the blood vessels providing more blood to the skin
• when the body is too cold, hairs stand up to trap an insulating layer of air, no sweat is produced, vasoconstriction happens in the blood vessels near the skin and shivering happens