Integumentary System

Skin, hair and nails are valued highly as traits of beauty, however, they are incredibly important for the healthy maintenance of the body. While it may be the most physically appealing body system, the integumentary system (which includes skin, hair, nails, glands and nerve endings), receives the most exposure to infection, disease and injury because it is the protective barrier against sun, wind, cold, heat, bacteria and physical trauma.

Proper elimination of toxins happens through the liver and bowels. However, if these organs cannot carry out their functions properly, or are overburdened from a poor diet of rich, oily foods and sweets, the skin becomes an additional means of elimination. With this added work, skin problems like acne are more likely to occur. The skin keeps the body from dehydrating and keeps its temperature constant. It also offers us sensors for touch and pain, and is capable of absorbing substances, including hormones like estrogen and poisons like lead.

The skin is a multi-layered system in a continual process of renewal that completes its cycle about every twenty-seven days. Since this renewal process is most active at night during sleep, sufficient rest is important.

The skin consists of several layers. The outer layer is the epidermis; the inner layer is the dermis, a tough yet elastic tissue; and the third layer, which is composed chiefly of fat cells, is called the subcutis. The epidermis repairs and renews skin tissue. The outermost cells are constantly worn away and replaced by new cells growing from below. The dermis contains the blood vessels, hair follicles, sweat glands and nerves. It is here where temperature, fluids and circulation are regulated. The fat layer serves as protection for the organs, bones and muscles, as a storehouse of energy, and as an insulator from the cold.

The primary function of hair is protection. Hair on the head protects the scalp from sunburn and injury, and prevents heat loss. Eyebrows and eyelashes guard the eyes from foreign particles. Hair in the nostrils and external ear canal prevent insects and foreign particles from entering through the nasal and auditory orifices. Nails are tightly-packed, hardened cells of the epidermis that form a solid cover to protect the ends of the fingers and toes from injury. Although nails are clear, most of the nail body looks pink because of the blood flowing beneath it. Nails allow us to grasp and manoeuvre small objects.

The glands associated with the skin are the oil glands, sweat glands, ceruminous glands (a type of sweat gland in the ear) and mammary glands. The excretions from these glands help to eliminate waste and toxins from the body, lubricate the skin and hair to keep them soft, and prevent foreign particles from entering the body. The mammary glands release milk from a woman's breast for nursing an infant.