Physiology of the Integumentary System
Physiology of the Integumentary System
Learning Objective: Examine the functions of the integumentary system.
The five functions of the integumentary system are listed and discussed next:
• Protection
• Sensory organ activity
• Temperature regulation
• Excretion
• Synthesis of vitamin D
Protection
Learning Objective: Describe how the integumentary system protects the body
The skin protects the internal organs by providing a flexible, waterproof barrier to the outside environment. It is part of the first line of defense from microbial pathogens, toxic chemicals, and physical tears, cuts, and abrasions. The keratin in our skin cells protects us from excessive fluid loss and dehydration. Finally, the melanin in the epidermis of the skin protects the body from damaging UV light. Skin is so amazing!
Temperature Regulation
Learning Objective: Describe how the integumentary system helps to regulate body temperature.
The skin is a very good thermoregulator. When we are cold, it constricts blood vessels close to the skin’s surface. This preserves body heat and lessens the heat loss to the surrounding environment. When we are hot, it can produce sweat that evaporates and cools us off. Because of the extensive blood supply to the skin, the body can help regulate and maintain a consistent body temperature. This is all part of homeostasis.
Excretion
Learning Objective: Describe how the integumentary system acts as a sensory organ.
The body can regulate the amount of sweat produced and the chemical content of the sweat. When we sweat, we lose water, electrolytes, and small amounts of other waste products. The integumentary system can excrete substances through the skin to help maintain the necessary chemical balance in the body as a whole.
Synthesis of Vitamin D
Learning Objective: Describe how the integumentary system is involved in the synthesis of vitamin D.
The synthesis of vitamin D is a vital function of the body, and it all starts in the skin. When skin is exposed to the sun’s ultraviolet rays, it manufactures a vitamin D precursor molecule. The molecule is carried to the liver and kidneys by way of the blood. The precursor molecule is then converted to the active form of vitamin D that the body can use. Research has uncovered many body functions affected by vitamin D, a few of which are as follows:
• Proper absorption of calcium
• Maintaining normal calcium and phosphorus levels in the blood; calcium helps maintain strong bones, proper blood clotting, muscle function, and immunity
• Protection against osteoporosis, high blood pressure, and some forms of cancer
• Preventing consistently low vitamin D levels, which can put a person at a higher risk for developing multiple sclerosis, heart disease, osteoporosis, and depression