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Posted by on Oct 12, 2015 in TellMeWhy |

Why Do We Have Hair?

Why Do We Have Hair?

The main purpose of hair is to protect the body. Hair keeps the top of the head warm in winter, and shields it from bumps and bruises. The hair in our nose and ears keeps dust and insects out of our lungs and inner ear. Eyelashes and eyebrows provide the same function for our eyes.

In addition, our eyebrows stop the drops of sweat that form on the forehead when we are hot, from running into our eyes and blurring our vision. The covering of tiny hairs on the rest of the body helps drain off perspiration, and alerts us if an insect is crawling on our skin.

Hair Comes From Where?

Whether hair is growing out of your head, arm, or ankle, it all rises out of the skin in the same way. It starts at the hair root, a place beneath the skin where cells band together to form keratin (the protein that hair is made of). The root is inside a follicle, which is like a small tube in the skin.

As the hair begins to grow, it pushes up from the root and out of the follicle, through the skin where it can be seen. Tiny blood vessels at the base of every follicle feed the hair root to keep it growing. But once the hair is at the skin’s surface, the cells within the strand of hair aren’t alive anymore. The hair you see on every part of your body contains dead cells. That’s why it doesn’t cause pain when someone cuts your hair with scissors!

Nearly every hair follicle is attached to a sebaceous gland, which is sometimes called an oil gland. These sebaceous glands produce oil, which makes the hair shiny and a bit waterproof. Sometimes, like during puberty, these glands can pump out too much oil and a person’s hair may look greasy.

Hair Today, Gone Tomorrow!

You have more than 100,000 hairs on your head, but you lose some every day. About 50 to 100 hairs fall out each day while you’re washing your hair, brushing or combing it, or just sitting still. But don’t worry; new hairs are constantly replacing those that have fallen out.

Each hair on your head grows for about 2 to 6 years. Then it rests for a few months and finally falls out. It is replaced by a new hair, which begins to grow from the same hair follicle. This cycle of hair growing, resting, falling out, and being replaced helps to maintain just the right number of hairs on your head.

Hair Comes in Many Colors

What kind of hair do you have — black and curly, blond and straight, or some other combination? Hair colors come from melanin, the substance that gives hair and skin its pigment. The lighter someone’s hair, the less melanin there is. A person with brown or black hair has much more melanin than someone with blond or red hair. Older people lose the melanin pigment in their hair as they age, making their hair look gray or white.

Often, a person’s skin color goes with the color of his or her hair. For example, many blondes have light skin, whereas many people with darker skin have dark brown or black hair. And don’t forget genes (genes are what you inherit from your parents): Usually, a kid’s hair color is determined by one or both parents’ hair color.

When it comes to type, your hair follicles make a difference. Some hair follicles are structured in a way that produces curly hair, whereas others send out straight hair. Follicles also determine if your hair will be thick and coarse or thin and fine.

Content for this question contributed by Lee Orr, resident of Roselle, DuPage County and Cook counties, northeastern Illinois, USA