The Basics of Hair


Hair is a protein filament that grows from follicles that are deep within the dermis. This filament, primarily made up of keratin, gives the hair its strength and elasticity. The fibers also act as a barrier against dust, microbes and other particles that can enter the body.

The hair is composed of three different layers: the medulla, the cortex and the cuticle. The medulla provides an insulating layer, and the cortex supplies a protective coating of long chains of keratin. The cuticle, a layer of lipids, repels water and gives the hair its shine.

It is important to know the makeup of your hair before you decide what type to get or how to care for it. You can improve your hair’s health by making sure it gets all the nutrients it needs, and by learning about how to properly treat it when you wash and style it.

A healthy head of hair contains about 100,000 to 150,000 individual hairs that grow at a rate of 0.5 inch (13 mm) per month. During growth, new cells grow into the root of the hair, which widens into a round hair bulb. The follicle is then filled with blood and nutrients to help the hair grow.

There are many different types of hair, with each one having a specific function. In mammals, the most common functions include protection from cold by insulating the body, sensory input and thermoregulation. In addition, some types of hair can communicate with other members of a species, and they can serve as camouflage for the animal.

Most human hairs are a mix of coarse and fine, with different lengths, textures, and pigmentation. Hairs that are dark in color are mainly coarse, while those that are light in shade are mostly fine.

They are characterized by a characteristic curl pattern that is in the DNA of every individual. This basic curl pattern is reasserted each time the hair grows. You can change the curl pattern slightly with heat or chemicals, but the basic characteristics remain.

The structure of the hair shaft is also important, as it affects the way a person’s hair looks and feels when it’s grown out. The shape of the hair shaft, as well as the angle it grows from the dermis, can help you determine your hair type.

It is important to understand how the hair grows and why it sheds. A person’s hair follicle cycles between anagen, or the growth phase, and catagen, or the resting phase, which involves shedding the old hair.

Anagen: The first growth phase takes between two to seven years, with a peak of growth occurring around the hair’s third or fourth growth cycle. It is this growth phase that accounts for the differences in the length of each strand and the number of strands present in the total.

In the anagen phase, new hairs are created in the root of the hair follicle, close to the papilla. The follicle is then filled from the bottom up with blood and nutrients to help the hair grow.