Hair Structure And Growth Hair Structure Each hair is a complex cellular structure and varies from one person to another. The structural form is basically the same: each strand, no matter how fine it may look, consists of three layers. The outer layer, or cuticle, is made up of overlapping scales which protect the inner layers. The next layer, or cortex, is made up of long thin cells, and is the most important because it gives the hair its elastic resilience, and contains the pigment which provides the coloring. The innermost layer, or medulla, is spongy tissue and the cells sometimes contain granules of color pigment. 
The part of the hair which is visible above the skin is the shaft, and the part that lies beneath the scalp is the root. The root is not a single unit; it is enclosed in a sac called the hair follicle, and at the base of this is a tiny nodule called the papilla. The papilla is the store house for nourishment of the hair strand. If you pull a hair out by the root, although there is a tiny globule of white at the end of it, you leave behind the papilla which will eventually manufacture and nurture a new hair. This is the reason plucking is never a permanent way to get rid of unwanted hair, and why hair loss through abuse and breakage will eventually be replaced.
Interlocked to the follicles are sacs containing sebum which lubricates the hair and gives it gloss and suppleness. An under active or blocked sebaceous gland means dry hair, an over active one means oily hair. Hair Growth
Each strand of hair grows out straight or curly depending on the inner structure of the root. If the root is smooth, the hair comes out as a perfect cylinder and is straight. If the root is distorted, the hair shaft is more oval, at times quite flat, and emerges as waves and curls. Whatever the texture, you usually have between 90,000 and 140,000 individual hairs on your head. Blondes, because their hair is finer, have the most; then dark-haired people, whilst redheads have the least although their hair is the thickest and therefore will appear the most abundant.
The life-span of a single hair can vary from a few months to several years. Each strand has its own cycle of growth, then a period of rest which ends in its falling out and being replaced by a new hair. This process is evenly distributed at different stages throughout the head and it is perfectly normal to lose a certain number of hairs every day. On average, hair grows at the rate of half an inch (13mm) a month, though this slows down as we get older. It grows faster during warm weather, and faster at night. The reason why some women can grow hair to their waists is because they have the combination of a quick growth rate and a relatively long life-span for each hair. It usually happens when you are young and in good health. Nothing can make hair grow faster and most hair, after reaching a length of ten inches (25... |
