The Interesting Life of Hair



They say you don’t miss something until it’s gone and this is very true for hair. Many of us only tend to become interested in where their hair comes from, what its composition is and how it’s made up – when it’s gone.

Early Days

We begin developing hair from our 22nd week in the womb. In fact, all of our hair follicles are formed by then – 5m in total with around 100,000 on our head. We will never have any more hair follicles than this, as we don’t generate new ones ever again.

You may have noticed that children tend to have denser hair than adults and this is because their scalps are smaller and have more hair follicles than adults.

The Composition

Hair is made up from two different structures – the follicle and the shaft.

The follicle is tunnel like and extends through the skin to the dermis. Made up of a number of different layers, it’s far more complex than it looks. At the bottom of the follicle is the area that contains the capillaries – these nourish the hair and are the only living part of the hair. The amazing things about these cells is that they divide every 1-3 days, far faster than any other cells.

The hair is also made up of two sheaths an inner one and an external one and these are created to protect the delicate areas beneath. The inner one runs along the hair shaft and ends below the sebaceous gland. The outer sheet runs up, along the band.

There are also muscles attached to hair, known as the erector pili this muscle is attached to the bottom of the fibrous layer around the external sheath. When we say your hair is standing on end, it’s because this muscle has contracted. When this happens the sebaceous gland is secreting oil.

This gland produces a compound known as sebum, which is used to keep hair and skin in the surrounding areas health.

Hair Shafts

The hair shaft is made up of three layers and is comprised of a hard protein known as keratin. One of the most notable things about this protein is that it’s dead and not a living structure. The middle layer of the hair shaft is known as the cortex, this is the largest part of the hair shaft. The outer layer of the cuticle, which is made up of a scale like substance. This is the part of the hair along with the medulla that gives the hair pigmentation and causes the hair to have a particular colour.

Hair grows at a rate of around 6 inches per year and we are the only mammal whose hair doesn’t shed due to the seasons. Our hair undergoes constant shedding and at any one time different hair will be undergoing different parts of the hair cycle, which we’ve written about here.

Hair is wonderful stuff and is quite an interesting, albeit overlooked part of the body. If you are looking for help with your hair or want to chat about your hair loss then get in contact with us at Skalp for a free consultation – we’d love to discuss about your options.

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