Integumentary system

The integumentary system is the skin and is a barrier to the external environment. Skin is made up of three layers:

• Epidermis
• Dermis
• Hypodermis.

The main functions of the skin are:

• Protection.
• Temperature regulation — the skin has an abundant blood supply, which is primarily for temperature regulation. For example, when we feel hot, the blood supply rushes to the skin surface and heat is lost through radiation. The skin also regulates temperature by perspiration (sweating), when we perspire heat is lost through evaporation.
• Sensory input — the skin has millions of nerve endings, which allow us to respond to the sensations of pain, heat and cold.
• Excretion of water and waste products.
• Manufacture of vitamin D.

Body temperature is the balance between the amount of heat produced and the amount of heat lost by the body. Body temperature remains fairly stable. Factors affecting body temperature are age, weather, exercise, emotions, stress, pregnancy, the menstrual cycle and illness.

The normal body temperature range for an adult is between 36.1 – 37.1 ºC. A subnormal temperature reading would be considered less than 36 ºC.