Each hair grows from a hair follicle, which is a part of the outer layer of the skin that is 'sunk' in to the deeper layers of the skin to form a tube-like sac. Each of us is born with a specific number of follicles, which cannot be changed. Each one can produce 20 or so hairs in a lifetime.

Each follicle’s nerves and muscles give the hair its tactile properties, allowing the slightest movement to be felt. When the muscles contract, the hair stands up more and pinches the skin, causing ‘goose bumps’.