Hair Structure - How Our Hair Works

Published 1/23/19, 3:46 PM by Fleur Scalp Care

Our hair structure can be a complex anatomy with various parts and components working together that affects the health of the hair. It’s good to know how our hair works in order to better understand the conditions, causes and treatments for any hair problems.

Hair Anatomy

Each hair strand is made primarily of two main structures - follicle and shaft. The follicle is the hidden part beneath the scalp and shaft is the visible hair we can see. Another way to visualize this is the biology of a plant’s roots and leaves.

Keratin is the building block of our hair. This fibrous protein makes up 90% of our hair and is also found in skin and nails. Keratin is a tough protein that is built up through a combination of different amino acids that you absorb through your diet.

Follicle

Hair follicle is the part of the hair beneath the scalp and anchors each hair into the skin. This is where hair begins to grow. It is comprised of various key components working together for hair growth.

Bulb is the bulb-shaped housing that surrounds the germinal matrix and papilla. It contains hormones that affect the hair growth and structure.

Germinal matrix or matrix forms around the dermal papilla where cell divisions takes place to form the source of hair growth. Melanin is also transferred to the hair giving it its natural pigmentation.

Dermal papilla is located at the bottom of the follicle. It is connected to the arteries and blood vessels where nutrients are circulated and waste are removed.

Sebaceous Glands

These oil glands are attached to follicles and produces sebum, the natural lubricant that protects the scalp and hair from drying out. Sebum is a natural moisturizer produced by our bodies designed to coat, nourish and protect our hair and skin.

Shaft

Hair shaft is the visible part of the hair that we see. Each shaft is comprised of three layers.

Cuticle

The outermost layer is the cuticle. This layer serves as the protective sheath around the hair.

Cuticles are made up of scales that works somewhat like a window blinds where it can be lifted up under certain conditions such as at certain pH levels (above 7.0). Moisture can be locked in and protected when the cuticles are closed which is why in dry and brittle hair, the cuticles are usually opened.

This is also why hair dyes include ammonia that increases the pH levels in order to open up the cuticles for the oxidation of new colour on the cortex layer.

Cortex

Cortex is the middle layer of the shaft. It is formed of elongated cells that makes up a fibrous structure providing hair its strength and elasticity. It also contains most of the hair’s pigment that makes up the hair colour.

Medulla

This is the innermost layer that acts as the pith or marrow of the hair. It is only present commonly in large thick hair.

Hair Growth Cycle

The average human has 100,000 - 150,000 strands of hair and loses about 50 - 100 strands daily.

Hair grows for a few years before going into a resting stage of few months where hair is shed. Each hair strand has its own stage of development. Hair growth cycle can be split into three stages - anagen, catagen and telogen.

Growing Stage

Anagen is the active growth stage of hair follicles beginning in the papilla. This growth phase typically lasts about 3-5 years on average.

Stopping Stage

At the end of the anagen stage, hair enters the transitional phase - catagen. Hair follicles begin to detach itself and shrink in preparation for the next stage.

Resting Stage

In this resting stage, hair follicles remain dormant and rests for a few months before the cycle repeats again.

Hair Problems

Due to the anatomy of our hair with various parts working together, the hair problems could be from a variety of possible causes. That’s why getting a detailed scalp analysis can help understand any hair conditions and its possible causes. Book your scalp analysis with us today.