- Night time routine
- Toddler Tips (Patience)
Explaining the hair shaft:
The structure of hair
A hair is made up of the hair shaft and the hair root, which contains the pigment cells which are so important for the color of the hair and the nourishing blood vessels, plus the sebaceous gland and the arrector pili muscle. The whole thing is called the hair follicle…
The hair shaft is a thin strand of hardened cells and is the part of the hair which is visible and touchable above the scalp. The diameter of a hair is between 0.04 and 0.12 mm. Light colored hair is usually finer than dark or red hair. Cross sections of hair can have various forms. Most hairs are round to slightly oval.
A hair consists of three layers:
The cuticle layer is the outermost layer of the hair and envelops the inner layers. Its tough, dense structure protects the hair. 6 to 10 layers of flat cells surround the cortex. They are arranged in a similar fashion to roof tiles. The outermost, exposed edges are open to the tip of the hair. The cuticle layer is colourless and therefore permits the light to shine through. It makes up a good 10 percent of the hair’s diameter.
The cuticle layer is important for the shine and elasticity of the hair. In young hair near the scalp, the edges of the cells lie flat on one another. The hair is only slightly porous and feels soft and supple. The surface reflects the light giving the hair its shine. The older a piece of hair is, the more physical and chemical stress it has been through. The edges of the cells open along the length and at the tips of the hair, or they are worn away. The hair becomes porous and feels straw-like and rough. It loses its gloss because the uneven surface no longer reflects the light evenly.
The cortex is the thickest of the three layers and makes up about 80 to 90 percent of the hair’s diameter. Hardened fibrous cells are bundled together. Every fibrous cell is made up of thousands of protein molecules. These long fibres are twisted together in bundles. The fibrous bundles are surrounded and held together by a mass of softer keratins. The cortex also contains the colour pigment melanin, which gives the hair its natural colour. White hair has no pigment and contains no melanin.
The medulla is in the center of the hair. Its diameter varies according to the thickness of the hair. In thick hair it is like a canal and gives the hair its stiffness. In fine hair it is only partly there or completely missing.
All biological processes and cell division takes place in the hair bulb. The hair bulb is bedded in a tight tube of skin, the hair follicle. The slight angle of the hair follicle’s position defines the direction of growth of the hair. Additionally the hair follicle has a straight form for straight hair and a bent form for curly hair. The hair follicle for hair on the scalp or on beards is 3mm on average and penetrates into the subcutaneous fatty tissue. The hair bulb is rounded like an onion. The papilla of connective tissue is put over this from below. In the hair bulb, around the papilla, are two types of cell: the matrix cells (keratinocytes, as in the epidermis) and the pigment cells (melanocytes). This is the living part of the hair. Micro-fine blood vessels (capillaries) grow in the papillae, near the cells. The life cycle of the hair, the cell metabolism and particularly growth all depend on the blood supply from the capillaries. This is comparable to the cell migration and cell transformation (hardening) in the epidermis. Nutrients are transported via the blood capillaries and waste products from the cell metabolism are transported away.