Surface covering of the body that protects it and receives external sensory stimuli, consisting of an epidermis over a thicker dermis.
The epidermis contains cells involved in immune defenses, sensory receptors, pigment cells, and keratin -producing cells. The last harden and migrate to the surface to form a dead, relatively dry outer layer of horny tissue that constantly sloughs away. The dermis contains sensory nerves and blood vessels within connective tissue . fat layer under the dermis provides nutritional storage, cushioning, and insulation. Skin disorders range from dermatitis and acne to skin cancer . Changes in skin colour (e.g., jaundice ) or texture may be clues to systemic disorders. See also dermatology ; hair ; integument ; nail ; perspiration ; sebaceous gland ; sweat gland .