A hair follicle is a tube-like structure in the skin that surrounds the root of a hair, and its main job is to grow that hair. According to Cleveland Clinic, hair follicles also help repair the skin after a wound or injury, help form new blood vessels, and help form new nerve cells.
When the skin is injured, cells from nearby hair follicles move quickly to the wound to start healing and assist the immune system’s white blood cells. People are born with more than 5 million hair follicles, over a million of them on the head, and the follicle is one of the few structures in the body that can stop working and then start again, which is what drives the cycle of hair growth, rest, and shedding.
Source: Cleveland Clinic: Hair Follicle
Image: Hair follicle under a microscope by Deset.apple, CC0, via Wikimedia Commons.