Basic Hair Knowledge
This is a VERY basic run down on hair structure.
The hair on your head is mainly made of a hard protein called keratin, and is usually formed in 3 layers. With a PH of between 4.5 and 5.5 your hair is considered to be acidic.
The outer layer, called the CUTICLE, is made up of overlapping keratin scales, you can imagine this outer layer looking like a pinecone.
The cuticle is the hairs protective layer and gives the hair its strength, a healthy cuticle is also important to give hair
it’s visual appeal, including smoothness and shine.
The middle layer, called the CORTEX, is made of keratinised protein and is the thickest layer of our hair. The cortex also contains most of the hairs natural melanin which gives our hair its pigment.
The central layer, called the MEDULLA, is like a thin hollow tube and appears to have no function. The medulla is usually absent in very fine and/or very blonde hair, although each head of hair can have a mixture of hairs with and without medullas.
Each Individual hair on your head has its own hair FOLLICLE.
The PAPILLA is like a bulb at the bottom of each follicle, it is fed by blood vessels. Cells in the papilla divide and create new hair fibres which cause the hair to grow. Stem cells at the bottom of each follicle produce melanocytes which produce MELANIN (The colour pigment in our hair and skin). When these cells die, the melanocyte production stops, meaning the production of melanin stops, and that hair will begin to grow white. Although our hair is created in the papilla which is fed by our blood supply, by the time we are able to see it, it is dead. This is why our hair isn’t able to repair itself once it becomes damaged.
Each follicle also has at least one sebaceous gland, which produces SEBUM. This is what we see and feel when our hair (or skin) is oily. Each follicle also has an arrector pili muscle which is responsible for the hair standing up as it exits the skin rather than lying completely flat. When we get goosebumps, this is the arrector pili contracting.
The hair grows in 3 phases.
ANOGEN: also known as the growth phase, usually lasts 2-6 years, this is determined by genetics. The longer the anogen phase lasts the longer the hair is able to grow. Up to 85% of the hairs on your head are in the anogen stage at
any one time.
CATAGEN: transitional phase, usually lasts about 2 weeks. Allows the follicle to rest and renew itself. The follicle shrinks and begins to push the hair upward, cutting the hair off from it’s blood supply and giving the appearance that this hair is still growing.
TELOGEN: resting phase, the follicle usually remains dormant for 1-4 months. The follicle will then begin to grow again, releasing its grip on the old hair at which point this hair will be shed and within 2 weeks a new hair shaft will begin to emerge starting the anogen phase again.
I might update this if I need to, to help explain things I say in the future but if you’re wanting to know more now, most of this stuff is easily googleable or feel free to ask questions! I just want this to be as easy to understand as possible 🙂