What is Hair made of ?

Our Hair – Its Consistence And Construction

Even though many of us view our hair as something special, it is part of our body, just like our fingernails. Since hair is part of our body, it can also provide clues as to our overall health. Our hair is complex, doing much more than playing a role in our appearance.

Hair starts to develop early in a fetus and by week 22, the fetus has developed all if its hair follicles. At this stage of development, the fetal body has about five million hair follicles. The head has approximately one million hair follicles, with almost one hundred thousand existing on their scalp.

As a fetus, we have more hair follicles than at any other time in our lives. As people age, they will notice the density of the hair on their scalp will decrease. One of the reasons for this is that our scalps expand as we age.

Hair consists of two parts – the follicle and the shaft. The follicle is beneath the skin while the shaft is what we see as our hair. The follicle contains a tunnel-like part of the epidermis which reaches down into the dermis.

There are several layers of the follicle, each providing a separate function. The base of the follicle holds the papilla, which helps nourish the cells of the follicle through tiny blood vessels or capillaries. Surrounding the bottom part of the follicle is the bulb. The bulb’s cells faster than any other cell within the body, approximately every 23 to 72 hours.

The follicle is surrounded by two sheaths, the outer and inner sheath. These sheaths help protect the hair shaft and help it grow. The outer sheath grows from the base of the follicle all the way to the apocrine gland. The inner sheath continues along the hair shaft and ends just under the sebaceous or apocrine gland opening. There is also a muscle the erector pili which is attached below the apocrine gland. Your hair stands up when this muscle contracts.

The sebaceous gland also produces sebum, a substance that helps to condition the skin and hair. Our body produces different amounts of sebum during our lifetime. Just after puberty, we produce the most sebum we will and production tapers off as we get older. Sebum production is less in women than in men as we age.

The shaft of our hair is constructed from keratin, a protein. The hair shaft consists of three layers. The keratin in our hair shafts is not alive. Most of the hair shaft consist of the cortex layer or outer layer. The inner layer is called the medulla and the second layer is the cortex. Hair colour comes from both the medulla and the cortex which both hold the hair’s pigment.

Our hair grows approximately six inches annually. Every day, our hair is in one of three stages of growth. The anagen phase is when the hair is actively growing. The catagen phase is considered transitional and is when hair growth stops and the follicle begins to shrink. The telogen phase is when the hair follicle rests.

Our hair is an important part of our body. It provides clues to our overall health and improves our self-esteem.