The Basic Structure of Skin : Hair

The Basic Structure of Skin : Hair

January 03, 2021

Hair - too little, too much, too dry, too oily, too gray, shedding -- there are so many challenges!

Each of these concerns will be addressed in different posts since each is a topic in and of itself.  Before understanding each topic, however, there are some hair basics that need to be covered first to lay the groundwork.  By understanding these facts, understanding hair products, hair promises, hair damage, and hair loss will come into better perspective.  

The first basic fact to get on the table  : the hair and the scalp are two different things.  

Think of your scalp like a farm. The scalp is the soil that grows a crop called hair. If the scalp is not healthy then the hair that grows from it cannot be either. If there’s inflammation, itching, irritation think of these issues as complications that can impact the way that your hair grows. It can make your hair grow out fine and wispy, or it can grow out damaged and easily breakable. Or, once those hairs grow they can actually be damaged by trauma from your fingernails.

Your hair is rooted deep in the dermis when it is actively growing. For this reason you cannot easily pull out and actively growing hair. What does actively growing mean? There are three eases to the lifecycle of a hair follicle. There is the growth phase, a transitional phase and a resting phase. The names for each of these cycles are anagen, catagen and it telogen, respectively.  

When hair is in the anagen, or actively growing phase, it is deeply rooted in the dermis of the skin. For this reason these hairs cannot be easily pulled out or removed. Many of my patients suffering with hair loss will comment that they avoid washing their hair out a fear that their hair will come out easily. The reality is that the hairs that do fall out easily are not actively growing - these are telogen hairs that have already entered the resting phase.   

The hair follicle may likely  already be transitioning into a new growth cycle. In many ways it does not make much of a difference whether or not the hair is washed because these hairs would inevitably fall out. Think of the hairs that come out of these follicles as likely making way for a new hair follicle entering into the antigen or growth phase. The challenge with this period of time is that the new hair growing in will be fine, peach fuzz like a ‘baby’ hairs. 

Hair grows like a blade of grass it starts off tapered at the end and gets wider as it gets longer. It takes time for this to happen. Unfortunately it can be a frustrating period of time because watching hair grow is like watching water boil or grass grow. It’s takes a while. 

Normally most of our hair is in the growth phase with a cycle across our scalp happening randomly with hairs entering the resting and then re-entering the growth phase again. 

At the base of every hair follicle is an oil gland. This oil or sebaceous gland is secreting oil that migrates down the shaft of the hair follicle. It takes about a day for this oil to migrate about an inch from the scalp. When we wash her hair, we are removing this oil. For people with short hair, it  can only take a day or two to ‘re-grease’ the hair that they have.Those with longer hair will find that it can take a few days if not longer to really feel like the hair has its oil back. In a future post we will discuss hair product and the impact they have here.

The last things to consider are the actual structure of the hair shaft itself. The surface of a hair follicle is actually not smooth, it is scaly. This plays a significant role in considering how hair products and hair color at work by lodging within the scale of these follicles. The second thing to consider is the actual transectional shape of the hair follicle. When you transect the hair follicle, the shape that you find actually can dictate if your hair is curly, straight, wavy, etc.

Lastly, hair color is dictated by the amount of melanin in the hair follicle itself. This melanin is produced in the cortex of the hair and moves down the shaft. The type and amount of melanin can dictate the actual pigment of hair.

We have several other posts to come on here so please stay tuned. There is so much in this category and it’s such an important topic to discuss!

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