Hair is the characteristic strandlike outgrowth of the outer layer of skin (epidermis) that forms an animal’s coat or pelage. Hair is present to some extent in all mammals, but in most it is sparse and confined to the head, genital regions, tail, and, in males, on the armpits, groin, and parts of the legs. The hairs of the eyebrows and eyelashes are distinct from these. Hairs have a wide range of cultural significance, both as indicators of biological sex and age and as markers of ethnicity and social status.
Hairs are composed of dead, keratinized cells. A typical human hair grows from a narrow tubelike pocket of the epidermis called a hair follicle. The follicle has its own sebaceous gland that produces a lipid-rich oil called sebum, which protects and moisturizes the hair and its surrounding dermis. As new cells form at the hair follicle, they push older cells outward forming a hair shaft. The hair shaft is composed of three main parts: the medulla, which makes up most of the hair’s length; the cortex, which gives it its strength and flexibility; and the cuticle, a thin, protective, translucent layer that contains much of the melanin that gives hair its color.
The keratin of hair is composed of protein molecules linked by salt bonds. These chains are arranged in bundles that run the length of the hair. Each bundle contains many microfibrils and protofibrils, which are made up of long chains of peptides that form a crystalline matrix. These microfibrils and protofibrils give the hair its tensile strength and elasticity. The melanin is located in the cortex and is produced by specialized cells called melanocytes. Melanocytes inject the pigment into keratin as it forms, thus determining the hair’s color.
As the keratin of hair ages, it becomes less flexible and more brittle. This is a natural part of the aging process and it occurs in all mammals. However, this process is accelerated by certain factors such as a diet rich in saturated fats and alcohol.
When describing a character’s hair, use descriptive words that convey emotion, mood, or personality traits. For example, you might describe a character’s hair as a “mop” or as “an aftermath of dreams and nightmares.” Also consider how a person moves their hair—for example, whether they finger-comb it or comb it, whether they move it forward, back, up, or to the side. A few inches off center works well for most people, and a good hairstyle usually allows for easy movement. Ask your friends and coworkers for feedback, especially if they have similar hair to the characters you are describing, as they may offer suggestions that might not have occurred to you. Aside from style, consider the hair’s texture and growth rate when deciding on a length. Short hair is anything above the shoulders; medium is shoulder to just below the back of the neck; and long is anything below the shoulders.