Hair Structure
Your hair has an interesting structure. It is made up of three distinct layers: the medulla, cortex, and cuticle. The cortex is responsible for your hair’s strength and colour, while the medulla is its innermost layer. Your hair is also composed of amino acids, which are the building blocks of proteins. These amino acids are held together by chemical bonds.
Hair Anatomy
The Hair Bulb
The Hair Follicle
The human hair follicle is a tubular structure that surrounds and supports the hair shaft. The cells in the hair follicle divide rapidly and produce new hair cells. As the cells move up the follicle, they harden and become keratinised. The sebaceous gland is attached to the base of the hair follicle and produces sebum, an oily substance that lubricates and protects the hair.
The Hair Shaft
It is made up of three layers: the medulla, cortex, and cuticle.
- The medulla is the innermost layer and is composed of cells that are filled with air.
- The cortex is the middle layer and is composed of cells that contain keratin, a protein that gives strength and flexibility to the hair.
- The cuticle is the outermost layer and consists of overlapping scales that protect the inner layers of the hair.
The Cuticle Layer
The cuticle is the outermost layer of the hair shaft. It is made up of cells that overlap each other like shingles on a roof. The cuticle protects the inner layers of the hair shaft from damage.
The Cortex Layer
The cortex layer is the middle layer of the hair shaft. It is made up of cells that are tightly packed together. The cells in the cortex layer are filled with a protein called keratin. The cortex layer gives the hair its strength and elasticity.
The Medulla layer
The medulla is the innermost layer of the hair shaft and is made up of a spongy, soft tissue. It is responsible for giving the hair its strength and elasticity.
The Roles of Melanocytes and Keratinocytes
The role of melanocytes is to produce melanin, which is responsible for the hair colour. Keratinocytes are cells that make up the hair shaft. The melanocytes inject pigments into the keratinocytes of the new hair shaft, which determines the colour of the hair. The colour lasts during the hair cycle, from when the hair is first growing to when it falls out.