hair

a threadlike outgrowth from the epidermis layer of the SKIN , which is a dead structure consisting of KERATINIC cells. The part above the skin has three layers: an outer CUTICLE , a CORTEX containing PIGMENT that confers colour, and an inner core. The lower end of the hair (root) lies within the skin and is expanded to form the bulb, which contains dividing cells that are continuously pushed upwards. This is contained within a tubular structure known as the hair follicle. A small erector pili muscle, attached to the hair follicle in the dermis of the skin, operates to erect the hair. See also TRICHORRHOEA .