Hair loss can be devastating. It mainly affects hair on the scalp, but hair may be lost from any hair-bearing surface of the body. For some people, losing their hair makes them feel like they’re losing their identity. Hair loss may deeply affect one’s self-esteem, and it can be the cause of depression.
Healthy hair starts with a healthy scalp. To maintain healthy hair, it’s important to keep the skin on your scalp clean and moisturized. Exfoliate once or twice per week by using either an exfoliating shampoo or natural scrub like oatmeal soap in the shower; this will help remove any dead skin cells that can clog pores and cause irritation. After you’ve finished washing your hair, apply conditioner generously all over your head (especially at the ends) before rinsing out to make sure there are no tangles left behind which may lead to breakage. Use products specifically designed for dry scalps when needed.
Understanding your hair’s structure may help you protect and preserve it.
An individual hair consists of two distinct structures:
- the hair shaft—which is the (keratinized) nonliving part above the skin surface.
- the follicle— which is the living part located under the skin and
The hair shaft consists of three layers:
- the cuticle,
- the cortex and
- in some hairs, the medulla.
The cuticle provides protection to the hair shaft and functions as a barrier against physical and chemical damage. The hair shaft may be damaged when the cuticle is disrupted, which can happen from combing wet hair, blow-drying it with a brush, or styling it with heated appliances. Heat can also break down the cortex and lead to damage if used excessively.
The follicle is the essential growth structure of the hair and has two distinct parts:
- the upper part consisting of the infundibulum and isthmus and
- the lower part consisting of the hair bulb and the “suprabulbar” region.
The infundibulum, the uppermost portion of the hair follicle extending from the opening of the sebaceous gland to the surface of the skin, is a funnel-shaped structure filled with sebum.
The isthmus is the lower portion of the upper part of the hair follicle (the section between the opening of the sebaceous gland and the insertion of the arrector pili muscle). Hair follicle stem cells are thought to reside in the “bulge” area of the isthmus, close to the insertion of the arrector muscle. Bulge cells are multipotent and generate the new lower (anagen) hair follicle. They are able to differentiate to form the hair shaft and inner root sheath. They also migrate upwards (distally) to form the sebaceous gland and can proliferate in response to injury.
The suprabulbar region of the follicle, below the isthmus and above the hair bulb, comprises three layers from outermost to innermost: outer root sheath, inner root sheath and hair shaft
The expanded onion-shaped portion of the lower hair follicle, including the hair matrix and the follicular papilla, is known as the hair bulb which is the active reproductive portion of the hair follicle.
The follicular papilla is responsible for determining the follicle type. The volume and secretory activity of the follicular papilla and also the number of matrix stem cells determine the size of the anagen hair bulb, the duration of the anagen phase and the diameter of the hair shaft. Moreover, the follicular papilla is an essential source of growth factors.
