Human hair is technically a kind of skin, according to KidsHealth, as are the nails on your fingers and toes. The human body usually has hair in every location except the lips, the palms of both hands and the soles of both feet. Although hair may seem like only an accessory you can grow, remove and style, it also keeps you warm and protects parts of your body from the environment and foreign matter.
Significance
Hair constantly changes because it goes through a continual cycle of normal loss and replacement. For example, people generally have about 100,000 hairs on their head, up to 100 of which fall out every day, according to TeensHealth. After hair falls out, new hairs grow through the same hair follicles. Hair loss is typically a problem only when new hairs do not replace the lost ones, which can lead to outcomes like baldness.
Features
Human hair grows faster in the summer and during the day than it does in the winter and at night, according to KidsHealth. Each strand contains a hair shaft that appears above the surface of the skin and a bulb-shaped root beneath the skin's surface. A tube-shaped follicle beneath the skin holds the hair root, which receives nourishment from blood vessels in an area at the bottom of the follicle called the papilla. The very hair bulb at the bottom of the follicle produces the melanin that produces hair color. Individual hairs consist of three layers: a soft medulla in the center, the main cortex that encloses the medulla and the hard protective layer on the outside called the cuticle.
Types
Human hair varies in color, length, texture and width. Your genes often affect variations, according to KidsHealth, although you can change some things about your hair temporarily by styling it. A substance called melanin is responsible for the color of hair. Darker hair, such as brown and brunette, has more melanin, and lighter hair, such as blond and gray, has less.
Length is related to two types of hair called terminal and vellus. Terminal hair is longer, coarser and darker. It provides protection and grows in areas like your head and, in men, the chest and face. Vellus hair is fine, short and soft. It provides insulation and grows in areas like the back and chest of women and prepubescent boys.
The texture and width of your hair depends on characteristics of your follicles. For instance, oval follicles produce curly hair and round follicles result in straight hair, according to Discovery Kids. Furthermore, large follicles lead to thick hair, while thin hair grows out of narrow follicles.
Considerations
Your body has approximately 5 million hairs in total, according to Discovery Kids, all of which are made of dead cells and a protein called keratin. Hair roots contain live cells that multiply as hair receives nourishment, which pushes the hair up and causes growth. However, the hair that you see above the surface of your skin consists of dead cells because it is too far away from the source of nourishment, according to KidsHealth. As a result, cutting visible hair does not cause pain.
Warning
Although it is normal for individuals to lose up to roughly 100 strands of hair every day, more extensive hair loss may be cause for concern. Reasons for abnormal hair loss include having a medical condition, taking certain medications, undergoing medical treatments, such as chemotherapy, and even wearing hairstyles that continually pull on your hair, such as tight ponytails. Fortunately, most hair loss in young people stops and hair grows back after you correct the related problems, according to TeensHealth.
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