Our hair is actually protein matter called keratin. And news is- what we see on our head, the jungle of protein that we so passionately care about, is actually `dead’. The living part of the hair s below the surface of the scalp, called follicle, which supplies these dead cells to keep our mane flowing. Our hair grows from follicles within the skin. The part of the hair inside the follicle (below the skin's surface) is known as the hair root, while the portion you see protruding from the head is the hair shaft. At the base of the hair root is the hair bulb where nutrients are received and new cells are formed.At the base of the follicle is a cluster of living cells called the papilla, which eventually forms hair. Next to the follicle is the sebaceous gland that actually keeps the hair shiny and looking vibrant. Excessive sebum activity can make hair very oily while lack of sebum activity can make it dry and lifeless. The arrector pili, a tiny muscle anchored to the follicle, respond to stimulus (fear or cold) causing them to contract and make the hair stand up straight.
The hair follicle is fed by blood circulated around it, which is why a healthy body makes great looking hair. Anemia or a fall in blood count can affect the hair. In fact one can go to the extent of saying that an unhealthy body is first reflected in unhealthy hair.
Taking nutrients from the dermal papilla, the hair bulb generates new hair cells. As these cells move up through the hair root, they mature through a process called keratinization, fill with fibrous protein and lose their nucleus. When the cell loses its nucleus it is no longer alive. By the time the hair emerges from the skin it is merely fiber made of keratinized proteins.
The fibrous protein emerging from the hair follicle as the hair shaft has a specific construction. It forms a strand with three layers: an outer covering of overlapping keratin scales called the cuticle, a middle layer of keratinized protein fibers called the cortex, and usually, a central 'core' of round cells called the medulla. A medulla is almost always found in coarse hair, and often is absent from naturally blonde hair and very fine hair.
In fact, our hair is approximately 91 percent protein, and is made up of long chains of amino acids. These chains are found within the fibers of the cortex of the hair. The amino acids of these chains are made up of the elements carbon, oxygen, hydrogen, nitrogen, and sulfur (are also the building blocks of the skin and nails) and are joined together by peptide bonds. Long chains of these peptide bonds are called polypeptide chains.
Catagen - The catagen phase is a transitional stage and 3% of all hairs are in this phase at any time. This phase lasts for about 2-3 weeks. During this time growth stops and the outer root sheath shrinks and attaches to the root of the hair. This is the formation of what is known as a club hair.
Telogen - Telogen is the resting phase and accounts for 10-15% of all hairs. This phase lasts for about 100 days for hairs on the scalp and much longer for hairs on the eyebrow, eyelash, arm and leg. During this phase the hair follicle is completely at rest and the club hair is completely formed. Pulling out a hair in this phase will reveal a solid, hard, dry, white material at the root. About 25-100 telogen hairs are shed normally each day.
Anagen - Anagen is the active phase of the hair. The cells in the root of the hair are dividing rapidly. A new hair is formed and pushes the club hair up the follicle and eventually out. During this phase the hair grows about 1 cm every 28 days. Scalp hair stays in this active phase of growth for 2-6 years. Some people have difficulty growing their hair beyond a certain length because they have a short active phase of growth. On the other hand, people with very long hair have a long active phase of growth. The hair on the arms, legs, eyelashes, and eyebrows have a very short active growth phase of about 30-45 days explaining why they are so much shorter than scalp hair.
*Hair Shape: The amount of natural curl a hair has is determined by it's cross-sectional shape. Hair that is most similar to a circle is straight and hair that is flattened and elliptical is curly or kinky. The more circular the shaft is, the straighter it is. The more elliptical the shaft is, the curlier or kinkier the hair. The cross-sectional shape also determines the amount of shine the hair has. Straighter hair is shinier because sebum from the sebaceous gland can travel down the hair more easily. The kinkier the hair, the more difficulty the sebum has traveling down the hair, therefore the more dry or dull the hair looks.
Ok I think I'll stop here. I just wanted to give a quick look at the biology of natural hair! Thanks for your support! Have a blessed one!