Hair Loss Basics – Hair Anatomy

Hair Loss Basics – Hair AnatomyThe human body is an incredibly complicated machine, and its myriad processes and functions are still being researched and understood. Look beneath the surface of even the seemingly simple aspects of our anatomy and you’ll find intricate structures and multipart growth and development cycles. There is no better example of this than the human hair. One hair may not seem like much, but there is much more going on than it may appear.

Hair Structure

Each human hair consists of three distinct parts:

  • The shaft. This is the part of the hair we can see above the surface of the scalp. Each shaft has three layers. The innermost layer, the medulla, doesn’t have any particular function. But the second layer, the cortex is extremely functional and vital. It is comprised of the durable protein keratin which gives hair its strength and durability, as well as its ability to uptake water. The outer layer, the cuticle, protects the shaft and helps it repel water. 
  • The follicle. This tube-like pouch laying just below the surface of the skin anchors the shaft and attaches it to the skin.
  • The hair root. The hair root attaches hair to the base of the follicle. The root is where hair actually grows and is nourished by blood capillaries.

Hair Growth Cycle

Like every other part of the body, hairs are comprised of cells. As new cells form at each hair root, they push the hair further out of the follicle.  As new cells form at the root, the hair is gradually pushed further and further out of the follicle, and farther away from the nourishing blood needed for cell growth. Without this nourishment, hair dies.

As hairs die, they are transformed into a hard protein called keratin. It is the follicle, which lies deep in the skin, that is indispensable for growing hair.

Hair growth is not a continuous or steady process. Instead, the growth of hair ebbs and flows in a cyclical pattern made of three distinct phases:

  • Anagen phase. The first phase is the growing stage. Hair grows at about one cm each month, and the anagen phase can last between two and five years.
  • Catagen phase.  As this phase begins, the bulb detaches from the blood supply and pushes the hair shaft up. The catagen phase can last several weeks.
  • Telogen phase. During this resting stage, which last about five months, there is no hair growth. At the end of the telogen phase, the hair sheds, and the follicle starts to grow a new one. At any moment, about 90% of the hair follicles of the scalp are growing hairs in the anagen phase while only about 10% are in the resting phase.

Any disruption to hair’s natural growth cycle can contribute to hair loss. For example, if follicles shut down and stay in the resting phase instead of growing new hairs, there will be less hair on the scalp. Interference with the formation of new hair cells at the root during the anagen phase can also be a cause for hair loss, as can the destruction of follicles due to trauma or burns.

Fortunately, there are effective ways to treat hair loss no matter what the cause. At the Hair Transplant Institute of Miami, our world-renowned hair restoration physicians have an unmatched understanding of the causes and treatment of hair loss and offer the most advanced and effective options for men and women alike.

Schedule an appointment with the Hair Transplant Institute of Miami today by calling 305.925.0222. We look forward to assisting you.


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