Integumentary System: It Is Only Skin deep
The integumentary system is comprised of skin, hair, nails, and sweat glands. The integumentary system is responsible for maintaining body temperature, is the first line of defense from pathogens, offers protection of the underlying tissue, holds sensory neurons responsible for sensory reception, controls the excretion of perspiration (part of temperature control), controls the pores (part of temperature control), and is vital for the production of vitamin D.
The skin is considered an organ, and it is the largest organ of the human body, usually about 14% of the body weight, and a surface area of up to 2 meters. The skin is comprised of two layers, the dermis and the epidermis. Some texts also classify a third layer called the subcutaneous.
Sweat glands are very close to the surface of the skin. When body temperature increases sweat glands and pores (which open up) secrete water droplets. As the water droplets (sweat) evaporates heat is removed. This process removes heat from the body. In conditions of high humidity, or where the skin is covered, the sweating mechanism is hampered and the body can not cool properly.
Hair grows from shafts located on the skin. The hair root is under the skin. And the hair bulb is where the hair grows from, which is also under the skin. Hair offers protection and warmth. During cool weather the small hairs may stand up which keeps warm air near the skin. Hair color, baldness, hair thickness, and texture are controlled primarily by genetics and to some extent by hormones (e.g. testosterone).
Like many other organs the skin can have medical problems. These include things such as; sunburns, acne, infections, blisters, and fungal infections (knows as athlete's foot). Because of the major functions of the skin it is important to seek medical help for any conditions that do not heal quickly.
Maintaining good skin health means avoiding intense and extensive exposure to the sun, always staying well hydrated, avoid smoking and drinking, and regularly monitoring for any signs of disease (e.g. infections, skin cancers, etc.).