To understand Hair Structure

Hairs are very important for our body because they are responsible for sensory transmission of our body. Hairs are very vital part of our personality and our looks. Our skin is provided with tiny pockets called hair follicles which give birth to hairs. Hair has many parts in structure but there are two basic parts called hair follicle and hair shaft. Hair follicles lie in the skin and hair shaft is the hair above the skin. Hair is made up protein cells and these cells die very quickly. These proteins are called keratin which is fibrous type.

Hair follicle:

Hair follicle is sac-like structure which is positioned below the skin and it is the structure where hair takes birth. Hair follicle is buried deep in the scalp fat. Within the hair follicle lies the hair root. An average human body carries around 2 million hair follicles and an average human head carries approximately 100,000 hair follicles.

Hair follicles is surrounded by sebaceous glands which secrets sebum. This sebum is secreted into the follicle canal. This sebum produced by the sebaceous glands is very important as it protects the hair and it acts like a natural conditioner. Dry or oily condition of hair is determined by the amount of oil produced by the sebaceous glands.

Hair follicle surrounds the hair root at its base. When the hair is in the growing phase, follicle has bulb shaped bottom. Here lies the dermal papilla in the centre of this bulb. Dermal papilla is very important for growth of hair as it carries tiny blood vessels. It is the dermal papilla which controls circulation of oxygen food in the hair. It also carries away the waste. Hair follicle also contains pigment cells, melanocytes at the top of dermal papilla. These melanocytes produce pigment which give color to the hairs.

The main parts of Hair follicles are

Inner Root Sheath: There is no pigment in this layer. This part is consists of three layers namely; the Henley layer, Huxley layer and the cuticle layer. Inner sheath ends below the opening of sebaceous glands. Out of three layers, root sheath is the part that touches the hair shaft.

Outer Root Sheath: This outer root sheath covers the inner root sheath. It starts from the lower end of the hair bulb to the start of sebaceous gland. Hair follicle is connected to skin epithelium with this part.

Fibrous root sheath: This outermost layer of hair follicle covers the vitreous layer. Entire hair follicle is coated by this which is itself consists of thickened collagen bundles.

Isthmus: It starts at the joint of the erector pili muscle and then it enters into sebaceous gland duct.

Suprabulb region: This region is consists of all the components of hair shaft, outer root Sheath, innere root sheath, vitreous layer and fibrous root sheath. It starts from the hair bulb and ends at isthmus.

Infundibulum: this starts from the upper portion of the hair follicles and is surrounded by epidermis, the outer skin layer.

Hair Shaft:

Hair shaft is the portion of hair you see above the skin. It is comprised of three layers which are concentric.

• Medulla is the innermost layer which gives elasticity to the hairs. It is present in only in scalp hairs which are relatively thicker than hairs on other parts. This layer is completely unaffected by any of the hair care processes and products.
• Then cortex is the middle layer of hair shaft. Cortex is very important part of hair shaft as it decides the structure, color, texture and strength to the hair. This layer pigment and can be altered by bleaching, dyeing, coloring, straightening or perming.
• And the last and the outermost layer is called cuticle. This is the protective layer which is thin and transparent. This layer is consists of overlapping scales. Inner structures of hair are protected by this layer. These tiny scales determine gloss and smoothness of your hair. If these cuticles lie flat, your hair will shine and look soft. Hairs look dry and frizzy if ends of cuticles are broken.