Hair grows from a single follicle - an indentation in the skin. Each hair follicle has its own blood, nerve and muscle supply. You’re born with a specific number of follicles, which can’t be changed, and the size of your hair follicle determines the thickness of your hairs.
At the base of your follicle, lying on the dermis (the deeper layer of your skin), is the papilla – the bud of hair where most growth takes place. The nerves and muscles surrounding your follicles give your hair its tactile properties, allowing you to feel the slightest movement. It’s these muscles that contract and give you ‘goose bumps’ when you’re cold or threatened. A scared cat or porcupine are exaggerated examples of this response.
The blood vessels that surround your follicles carry the nourishment your hair needs to grow. This is one of the reasons why your diet is so important for healthy hair growth and strength.