The Structure of Hair and What It’s Made Of


Hair is not just a feature, it’s an essential part of the body. It traps dust and other particles around the eyes, nose and ears and provides warmth to vulnerable areas. It also allows us to express our personal style, and it grows back if damaged. It’s a complex structure, made of dead cells containing keratin, that grows out of a small hole in the skin (the hair follicle). This article gives an overview of the structure of hair, how it grows and what it’s made of.

When hair is healthy, it grows at a rate of about one inch a month. But if your diet, the environment or genetics cause problems with your hair, you may experience slower growth or even total loss of your hair.

Each hair starts inside a follicle in the skin, which looks like a tiny, round cylinder with a rounded bottom. At the base of the follicle is an artery that supplies blood to the growing hair cell. As the cell divides, it creates a new strand of hair and it then gets pushed upward through the follicle. The top of the follicle contains a muscle (the arrector pili) that can make the hair stand up and it’s lined by nerves that sense movement of the hair.

The cells that form a hair strand are called keratinocytes, and they become keratinized—hardened by an insoluble compound called keratin—before being pushed out of the follicle. This forms a shaft of hair that’s covered by the cuticle, which locks moisture in. The hair cortex is the middle layer of the strand and it contains long chains of keratin that give the hair its strength, stiffness and elasticity. It also contains pigments produced by specialized cells called melanocytes that add color to the hair.

In the human scalp there is a third layer of hair, the medulla, that extends into the scalp. Its main function is to provide support to the follicle and it also helps with hair growth.

Besides its practical functions, hair has a lot of cultural significance. It’s often used as a way to identify gender, race and ethnicity. It is also an important symbol of freedom in many cultures. Head shaving is a common punishment for criminals, and in some cultures the removal of hair is seen as a sign of mourning. In addition, many types of hairstyles and colors have a social meaning as well. For example, African-Americans have a long history of using their hair to enhance their self-image and it has also had significant political implications for that group.