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Hair sciency bit
The hair begins in the Hair Follicle, which is situated deep in the skin in what’s called the Epidermis. The hair follicle has its own blood supply which enables the hair to stay alive and grow. In the hair follicle, you can also find nerve branches which respond to touch and temperature changes. It is because of these tiny nerves that hair removal can be painful! There are tiny muscles called ‘arrector pili’ attached to the outer hair shaft in the epidermis. When the nerve endings sense touch or a temperature drop, these muscles contract and pull the hair follicles vertical and pinch up the surrounding skin to produce ‘goose bumps’ Hair colour is also produced in the root of the hair by ‘melanocytes’ A hair growth cycle occurs in each follicle. When the hair is growing, it is in the anagen phase. The Anagen phase is then followed by a short transition period lasting 2 weeks called the Catagen phase. During this time the hair bulb and lower part of the hair follicle break down. The hair has now become a club hair in the shortened follicle and remains like this until the next phase. The next phase is known as the Telogen phase. Telogen last 3-4 months in terminal hairs (scalp, eyebrows, eyelashes, beard) and 2.5 months in vellus hairs (the soft light hairs that cover the whole body). At the end of telogen, a new hair root is formed and the follicle is lengthened. The old hair is shed as new hair develops below and the cycle begins again. The picture below shows the growth cycle of hair.
FACTS
On the scalp, the average rate of hair growth is 0.35mm a day Life span of a scalp hair is between 1 ΒΌ and 7 years with 3 years being an average growing period. Eyelashes and eyebrows are replaced every 4 – 5 months A loss of between 50 – 100 hairs daily is normal for a scalp. Pregnancy reduces hair loss temporarily but after birth the drop in sex hormone levels causes many more hairs to fall out at once. Hair is made up of a protein called ‘keratin’
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