Understanding How Hair Grows - The hair system is known the pilosebaceous system. It consists of four main parts: 1. Follicle - the hair canal 2. Papilla - the organ that feeds hair growth 3. Sebaceous Gland - the associated oil gland 4. Hair - shaft or structure which has hardened (keratinized) Follicle A hair follicle is an indention in the skin. The inside of each follicle therefore is much like the skin's surface being an inward fold into the skin with a mechanism for producing a hair. The lower portion of the follicle has an expanded shape and is called the follicle bulb where there is an area of actively dividing cells called the hair matrix. This is the source of hair production. The follicle and the hair it produces continue through repeated cycles of growth and rest. Papilla At the base of the follicle lies a tiny structure made of skin- related cells called the dermal papilla which feeds the newly formed hair cells from its blood supply. These newly formed hair cells grow continuously and die continuously, forming a hardened or keratinized structure - the hair shaft. The hair shaft continues to grow outward from the follicle base. Sebaceous Gland The sebaceous glands or oil glands are located close beneath the surface of the skin over the entire body. There are a large number concentrated in the facial area. The oily material secreted is called sebum. Sebum lubricates the hair shaft and the skin. Hair The papillary region is often referred to as the "hair root," the portion which grows below the surface of the skin which is contained within the follicle canal. The hair shaft is the portion of the hair that grows above the skin surface. Generally speaking, two types of hair are produced by the follicle: vellus terminal Vellus hair is like "peach fuzz" and it is normally found on a woman's cheek or a young child. It is soft, downy and colorless. The follicles producing vellus hair are shallow, and the hair shaft produced is relatively short. Vellus hair is normal in women and is not treated with permanent hair removal techniques such as electrolysis. Terminal hair is deeply rooted, coarse, and colored. Terminal hair begins as the peach fuzz type but later develops color and some degree of coarseness at which point it becomes the terminal type. Terminal hair grows from the scalp, eyebrows, underarms, pubic area, and other parts of the body. It is terminal hair which many people regard as unwanted and therefore try to remove from certain body areas. |
