After understanding the functions of hair and the relationship between hair and your skin (explained in my previous articles), it's now time to move to the hair itself. To make sure that your knowledge of your own hair is complete, you need to know what is hair follicle, hair shaft and dermal papillae.

What is Hair Follicle?

Like the human skin, the follicles (or the root portion of the stands) are composed of distinct layers. The first layer is called the trichelemma: the outermost portion of the hair follicle. Beneath the actual ‘hair' (the cuticular scales) is the trichelemma.

The second layer is called the inner root sheath. This layer precedes the trichelemma and is composed mainly of proteins and cuticle material. This inner layer is one of the closest layers to the very bulb of a follicle.

Finally, the last layer is called the root bulb of the follicle. This portion of the follicle contains the primordial site of cell reproduction. This is where all the organic magic begins: with the production of so-called hair cells. This is also the site that receives the most damage when people decide to use harmful chemical-based hair colorants and toners.

What is Hair Shaft?

Now that you know the parts of the follicle it's now time to move to another important layer, known as the “shaft”. The shaft, as the name implies is the tubular, protein-bound hair that we see and feel. The first layer of the shaft is the cuticle. This layer is at the very surface, and is the most visible portion of a shaft to the naked eye.

The second layer of the human hair shaft is the cortex. If we are to use a tree as illustration, then the cuticular scales are the bark of a tree, and the cortex is the actual trunk of the tree. The trunk is protected by the bark, the same way the cuticular scales protect the cortex of the hair shaft.

The final layer of the shaft is the medullas. This comprises the most central portion of the shaft. Take note that these would not be found in newly emerging shafts. It would be present however, in strands of hair that are nearing their telogenic phase.

What is Dermal Papillae?

If our general genetic characteristics are determined by the union of genetic materials from two parents (one male and one female), then the hair also is the offspring of distinct, primordial cells. These cells are called the “dermal papillae”.

Though scientists are still debating the more specific functions of these primordial cells, their basic function is to characterize the hair that is to be produced. The genetic information regarding how long and how rough a person's hair would be, is determined by the dermal papillae.

This might be telling why people from different territories in the world have different hair types: because it is in the interest of genomic preservation to adapt the hair type to the general climate of a person's long-time home.