Human hair performs several functions. It protects the skin from environmental influences. It responds to external input and translates this information into neurological impulses that are interpreted as sensory stimuli by the brain.

Hair is much more complicated than it looks. You can feel it at the root when it moves or gets pulled. It protects your skin and traps particles like dust around your eyes and ears. You can express yourself through your hairstyle. If your hair gets damaged, it can renew itself without scarring.

Head hair protects the scalp against the burning sun and helps hold in body heat. Eyelashes and eyebrow hair help keep foreign matter out of the eyes, and hair in the nostrils and ear canal help catch dust, debris and even insects from entering the body. Nostril hair also helps regulate the temperature of inhaled air before it enters the body.

The function of a hair follicle is to grow your hair. In addition to promoting hair growth, your hair follicles do the following jobs: Help repair your skin after a wound or an injury. Form new blood vessels (angiogenesis). Form new nervous system neuron cells (neurogenesis).

While some body hair serves important health functions––nose hair protects against bacteria getting in our airway––the most prominent hair, on our scalp, is primarily aesthetic. “Right now, the way we use hair, it’s really a form of self expression and empowerment,” says Loren Krueger, an assistant professor of dermatology at Emory University.