How Long and Thick Is Your Hair?

Hair (pronounced hr) is a fibrous protein filament that grows from follicles in the skin. It is one of the defining characteristics of mammals. Except for areas of glabrous skin (the palms of the hands, feet and lips), almost all parts of the body have hair follicles. The follicles produce two kinds of hair: fine vellus hair and thicker terminal hair.

There are a lot of things that can affect the length and thickness of your hair, from genetics to hormones to the condition of your scalp and follicles. But the most important factor is your diet. If you’re not getting enough nutrients, your hair can become dry and brittle – or even fall out altogether.

Each hair is made of tiny cells that are arranged in a spiraling helix, and embedded in a matrix of proteins called keratin. The helix-like arrangement of amino acids is what gives hair its strength. The proteins in hair also contain fatty acids, which give it its smooth, shiny appearance.

The outer layer of the hair is a protective cuticle. The cuticle is a layer of flattened cells that overlap like tiles on a terra-cotta roof and protect the inner, softer, more flexible part of the hair. This part is called the cortex, and it’s what gives hair its color, texture and strength. There’s also a soft, spongy center inside some hairs called the medulla. This part isn’t as important as the cortex, but it can have an effect on how your hair feels when you touch it.

Some people have a “fast” hair growth cycle, and some have a “slow” hair growth cycle. This has to do with your genes and the level of certain hormones, especially estrogen. When estrogen levels decrease, your hair can slow down or even stop growing.

Most of us think of hair as something that covers our heads and necks. But it also can be found on the ears, eyelashes, nose and other parts of our bodies. There are even some plants that have hair.

Hair is often a mark of social status. It can be dyed or straightened to change its appearance, and it can be cut into a style that reflects a person’s personality or fashion sense. It can also be used to convey a message or to make a statement about an individual’s attitude, beliefs, religion or political affiliation. Some people use their hair to identify with a particular subculture or to express their creativity. For example, many rockers and metalheads have long hair, which they often style in a mohawk. And the longer, spikier hairstyles popular among punks and other young countercultureists are often dyed or bleached bright colors.