Structure of Hair, Science of Hair, Structure of Hair Root & Hair Shaft, Chemical Composition

Hair is an important part of the human body that protects the scalp and enhances personal appearance. In cosmetology, understanding the structure and science of hair is essential for performing hair care treatments, styling, and chemical procedures safely and effectively. Hair is mainly composed of a protein called keratin and grows from hair follicles located in the skin.

Science of Hair

Hair is formed from specialized cells that produce keratin, a strong fibrous protein. These cells are found in the hair follicle beneath the skin. As new cells are produced in the follicle, older cells are pushed upward and form the visible hair strand. The part of the hair that we see above the skin is called the hair shaft, while the part located below the skin is known as the hair root.

Structure of Hair

The hair structure is divided into two main parts: the hair root and the hair shaft. Each part has a specific role in hair growth and protection.

Hair Root

The hair root is the portion of the hair located beneath the surface of the skin. It is enclosed within the hair follicle and is responsible for hair growth. The root receives nutrients and oxygen through blood vessels, which help in the formation of new hair cells.

The hair root includes several important components:

• Hair Follicle: A tube-like structure in the skin that holds the hair root.
• Hair Bulb: The enlarged base of the hair root where hair growth begins.
• Dermal Papilla: A small structure at the base of the hair bulb that supplies nutrients to the hair.
• Sebaceous Gland: Produces oil (sebum) that keeps the hair soft and moisturized.

Hair Shaft

The hair shaft is the visible part of the hair that extends above the skin surface. It is composed of dead keratinized cells and does not contain nerves or blood vessels. The hair shaft is responsible for the hair’s strength, color, and texture.

The hair shaft consists of three main layers:

• Cuticle: The outermost layer made of overlapping cells that protect the inner layers of the hair.
• Cortex: The middle layer that contains pigment (melanin) and gives hair its color, strength, and elasticity.
• Medulla: The innermost layer that may contain air spaces and contributes to the thickness of the hair.

Chemical Composition of Hair

Hair is mainly composed of keratin protein, which gives it strength and durability. The chemical composition of hair includes several elements that contribute to its structure and properties.

• Keratin Protein: The primary component of hair responsible for its strength and structure.
• Carbon: A major element that forms the basic structure of hair.
• Oxygen: Helps maintain the chemical balance of hair.
• Hydrogen: Contributes to the flexibility and strength of hair.
• Nitrogen: Important for the formation of protein in hair.
• Sulfur: Responsible for the strong bonds that give hair its shape and durability.

Importance in Cosmetology

Understanding the structure and chemical composition of hair helps cosmetologists perform hair treatments safely. Knowledge of hair science is essential for services such as hair cutting, coloring, chemical treatments, and hair care procedures.

Conclusion

Hair is composed of two main parts: the hair root and the hair shaft. The hair shaft consists of three layers—cuticle, cortex, and medulla—while the root is responsible for hair growth within the follicle. Hair is mainly made of keratin protein and several chemical elements that provide strength and flexibility. Understanding hair structure is essential for proper hair care and cosmetology treatments.