What Is Hair and How Does It Grow?

Hair is a living tissue that begins growing inside a hair follicle, a tiny saclike hole in the skin. Each follicle has an artery that supplies nutrients to the cells that will eventually become hair. Once those cells have made enough keratin, they’re pushed out through the skin’s surface as a shaft of hair. Each hair has two or three layers: the cuticle, cortex and medulla. Each layer serves a different function in the structure of your hair.

The outermost layer is the cuticle, which protects the underlying keratinous fibers from the environment. The cuticle is composed of flattened, overlapping keratin cells. The keratin is insoluble in water and provides the hair with its waterproofing. The keratin cells also form bundles that give hair its strength, flexibility and resistance to damage.

Next is the cortex, which carries most of its color pigmentation. The pigments are produced by specialized cells called melanocytes and deposited within the hair cell’s keratin granules. The cortex also contains bundles of long keratin protein molecules, which gives hair its color and texture. Finally, the medulla, which is only present in the thicker hairs on your head, has a fragile structure that resembles bone marrow.

Once the follicle’s cells reach the surface of the epidermis, they become dead. As the hair pushes out of the follicle, it pulls a sebaceous gland (also known as an oil gland) to the surface, where it releases oils that help nourish the follicle as it grows. As the follicle develops, the oil it produces helps to protect the living hair cells within.

Each strand of hair has a diameter of about 60 micrometers and is made of a material known as a keratin. The keratin in your hair is tough and durable, but it’s not indestructible. Over time, exposure to the sun, hot tubs or harsh shampoo can cause the keratin in your hair to break down and wear away. That’s why it’s important to be gentle with your hair.

Your hair can tell a lot about you. The way it moves reveals your character’s style, and the texture of your hair is a good indicator of how you carry yourself in your daily life. Whether you have short, wavy hair or long, black locks, the style and texture of your hair is a reflection of your personality. And the way you carry yourself in turn reflects how your character interacts with others. So the next time you write a scene, remember to show us how your character’s hair moves. It’ll make your story more compelling and help the reader to see your character as a real person.