Hair Anatomy
Hair is a Keratinized protein filament that grows through the top layer of the skin (epidermis) from follicles deep within the skin (dermis).
Human beings have three different types of hair.
Languo: The fine hair covering the entire body of the foetus.
Vellus: Very short, fine, scarcely visible hair, covering most parts of the bodies of both sexes.
Terminal: fully developed hair, generally longer, coarser thicker and darker then the vellus type.
Hair is much more complicated than it appears. It transmits sensory information and creates gender identity. Hair is important to the appearance of men and women, giving confidence, self esteem and good looks. There is hair on all the major visible surfaces of the body.
Hair has two separate structures.
1. The hair follicle which is in the skin.
2. The hair shaft which is what we see.
The skin plug or otherwise referred to as the follicular unit contains, in this case, a single hair; it is complete with its neurovascular bundle and sebaceous gland, which must be meticulously removed and transplanted by the hair surgeon, using the H+ 2.0 FUE Hair Transplant Procedure
Hair Follicle
The follicle is a stocking-like structure that contains several layers with different jobs. At the base of the follicle is a projection formed like sticking a finger in the bottom of a stocking and pushing it in a small amount. This projection is called a papilla and it contains capillaries, or tiny blood vessels, that feed the cells. The living part of the hair is the bottom part of the stocking surrounding the papilla called the bulb. This bottom part is the only part fed by the capillaries. The cells in the bulb divide every 23 to 72 hours, faster than any other cells in the body.
The follicle is surrounded by two coverings- an inner and outer sheath. These sheaths protect and mould the growing hair shaft. The inner sheath follows the hair shaft and ends below the opening of a sebaceous (oil) gland. The outer sheath continues all the way up to the gland. A muscle called an erector pili muscle attaches below the gland to a fibrous layer around the outer sheath. When this muscle contracts, it causes the hair to stand up. The sebaceous gland is important because it produces sebum which is a natural conditioner. More sebum is produced after puberty. The sebum production decreases in women throughout their lives. The production also decreases in men, but not as much as in women.
Hair Shaft
The hair shaft, which is what we see is made up of dead, hard protein called keratin in three layers. The inner layer is called the medulla and may not be present. The next layer is the cortex and the outer layer is the cuticle. The cortex makes up the majority of the hair shaft. The cuticle is formed by tightly packed scales in an overlapping structure similar to roof tiles. Most hair conditioning products attempt to affect the cuticle. There are pigment cells that are distributed throughout the cortex and medulla giving the hair it's characteristic colour.
Hair Growth
Hair growth occurs in cycles, in three main phases.
1. Anagen Phase
It is the active growth phase when cells in the hair bulb, which is at the root of the hair, divide rapidly. This adds 1cm to the hair shaft every 4 weeks. The scalp hair remains in this phase for around 2-7 years. The exact period varies from person to person. Normally 90% of your hair is in the anagen phase at any one time.
2. Catagen Phase
This comes after the anagen phase. This lasts 2-3 weeks and is the end of the hairs active growth phase. Approx 10% of your hair are in the catagen phrase.
3. Telogen Phase
This is the resting phase, it lasts 2-3 months. It applies to approximately 1% of your hair at any one time. At the end a club hair… which is dead is produced, this is subsequently shed. 50 to 100 club hairs are shed daily.
