Dermatology is the branch of science which deals with the study of skin, nails, hair and its diseases.
The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch, heat, and cold. Skin has three layers:
1. Epidermis: This the outermost layer of skin, provides a waterproof barrier and creates our skin tone.
2. Dermis: This is a thick layer that contains tough connective tissue, blood capillaries, sensory nerve endings, hair follicles, fat cells and sweat glands.
3. Subcutaneous tissue(hypodermis): It is made of variables number of fat cells and connective tissue.
The nail is a horn-like envelope covering the tips of the fingers and toes in humans, most non-human primates, and a few other mammals. The nail organ is also an integral component of the digital tip. It is a highly versatile tool that protects the fingertip, contributes to tactile sensation by acting as a counterforce to the fingertip pad, and aids in peripheral thermoregulation via glomus bodies in the nail bed and matrix.
The Hair is made of a tough protein called keratin. A hair follicle anchors each hair into the skin. The hair bulb forms the base of the hair follicle. In the hair bulb, living cells divide and grow to build the hair shaft. Blood vessels nourish the cells in the hair bulb, and deliver hormones that modify hair growth and structure at different times of life.