Training Manual – Science Of Hair

The Science of Hair

At Harley Waxing, we believe that understanding the structure of the hair and skin, and the way hair grows, is an essential part of providing a professional waxing service.

Structure of the Hair

Keratin is the main building block of hair. It is a protein that protects our hair from breakage and is also found in our nails and skin.

The Hair is Divided into Two Principal Parts:

• Hair root: The portion of the hair structure beneath the skin’s surface within the hair follicle. The hair root extends from the surface to the bulb.
• Hair shaft: The portion of the hair structure extending above the skin’s surface.

Structures Associated with the Hair Root:

• Hair follicle: A tube-like depression or pocket in the skin or scalp, encasing the hair root.
• Hair bulb: A thickened, club-shaped structure forming the lower part of the hair root.
• Hair papilla: Small, cone-shaped elevation found at the bottom of the hair follicle that fits into the hair bulb. Within the papilla is a rich blood and nerve supply that contributes to the growth and regeneration of the hair.

Structures Associated with the Hair Follicle:

• Arrector pili muscle: A small involuntary muscle attached to the underside of the hair follicle. Fear or cold causes the muscle to contract, making the hair stand on end.
• Sebaceous or oil gland: These are connected to the hair follicles. The secretion of sebum from these glands gives lustre and pliability to the hair.

The Hair Shaft has Three Layers:

• Cuticle: The outer layer of the hair shaft is thin and colourless. It serves as protection to the cortex.
• Cortex: The middle layer of the hair shaft, which provides the strength, colour and texture.
• Medulla: This is the central core that contains the living matter.

The Hair Growth Cycle

As follicles cease to produce hair, they shrivel up, and the lower part of the bulb degenerates. These resting follicles are simpler and much shorter structures than the active ones. At the base of the resting follicle, the hair, if still present, forms a club that is anchored by keratinous strands to the epithelial sac. Close inspection of a hair removed in the resting stage will show the shallow position of the hair. It sits almost on the skin’s surface and has a ‘full stop’ on its root end. This rounded club is a ball of cells and the lower part of the epithelial sac, called the hair germ, from which the next generation of hair develops.

The Four Stages of Hair Growth:

• Anagen: The actively growing hair. The bulb is thick and fleshy.
• Catagen: The follicle shrinks, and hair growth slows.
• Telogen: The hair is resting, awaiting new growth. The bulb is non-existent.
• Exogen: At this stage, the hair falls out.
  

The Anagen, Catagen, Telogen and Exogen sequence of events repeats itself until an internal or external influence causes a cessation in regrowth.

Factors That Influence Hair Growth:

The amount of hair we have on our bodies depends upon many factors, including the seasons, climate, hormones and hormonal changes, medication, gender and overall state of health.

• Blood Circulation: Necessary to nourish and detoxify the papilla, which is very sensitive to changes in blood circulation.
• Mental Health: Emotional shock, overexertion or severe stress can cause hair loss.
• Genetic Factors: Inherited conditions like baldness or hormonal imbalances.
• Medications: Chemotherapy, antibiotics and tranquillisers.
• Diet: Sudden or total changes in diet, iron deficiency, and obesity can all influence hair growth.
• Endocrine System: Puberty, pregnancy, hysterectomy, dysfunction or disease.

Different Types of Hair Growth:

• Superfluous Hair: A general term for any unwanted hair.
• Lanugo Hair: Very fine hair that is formed on the unborn foetus. It lacks a medulla and sheds shortly after birth, whereafter permanent hair replaces it.
• Vellus Hair: Fine hair that covers most areas of the body, except for the palms of the hands and soles of the feet. These do not contain a medulla.
• Terminal Hairs: Coarse, visible hairs on the scalp, underarms and pubic areas.

Ingrown Hair Types:

Ingrowns are hairs that, on emerging from the follicle, either grow along the skin’s surface or turn back into the follicle opening and become compacted. A keratin plug, formed by dead skin cells and sebum, is a typical cause.

• Friction ingrown hair: Friction causes the hair to grow back into the follicle.
• Trapped ingrown hair: Hair has been trapped in the follicle and no longer continues to grow.
• Common ingrown hair: Hair cannot exit the follicle and continues to grow under the skin.
• Tornado ingrown hair: When hair cannot exit the follicle, it can turn back and continue to grow in a spiral motion.

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