Have you ever wondered why a minuscule chip in your tooth can cause an unbelievable amount of pain but slicing your hair to pieces is completely painless.  I know a haircut can sometimes feel like a painful experience but unlike teeth hair doesn’t actually have any nerves.

A hair follicle is composed of three parts; the root which is below the skin surface, the bulb which feeds nutrients to the root and the shaft which is the hair we see above the surface of the skin.  The main purpose of hair is to provide us with insulation (preventing warmth from escaping); it cushions our body during impacts and protects our skin.

To understand why you don’t feel pain when you get your hair cut; you must first understand how hair grows.  The bulb provides the nutrients necessary to make new cells.  The cells grow underneath the surface of the skin forming the hair follicle.  This hair follicle is very much alive when it’s below the scalp surface; this is required in order for the hair to grow.  When someone pulls your hair, it’s these nerves that are being stimulated causing pain.  As the hair grows above the surface of the scalp the follicle fills with a fibrous protein and dies; a process known as keratinization.  By the time you are able to see the hair follicle it is simply a strand of dead protein cells, similar to our nails.  If hair had nerves it would cause an incredible amount of pain since hair is constantly breaking and falling out.

Teeth are composed enamel dentin and pulp.  The enamel is the hard outer layer of the tooth; it protects the tooth by providing a hard shell that’s difficult to break.  Dentin is the layer found just underneath the enamel and is essentially the bulk of the tooth.  When the enamel is worn away the dentin becomes exposed and deteriorates quickly. The pulp is located in the center of the tooth; this is where the pain nerves are located.  Unlike hair, once an adult tooth has broken or fallen out it does not repair itself or grow back.

These nerves found in teeth serve some very important purposes.  They are stimulated by heat, cold, acid as well as infections.  When you chew the muscle in the jaw actually has enough strength to break your teeth.  The nerves in our teeth let you know how hard you’re biting down, thus preventing your teeth from breaking when you chew food.  They let you know if something too hot, cold or acidic.  These nerves also tell you when there’s something wrong with your teeth, like an infection in the root.

If teeth didn’t feel pain then they could get broken or worse infected and rot; you would never know until the teeth fell out.  Imagine having to go get your hair cut if your hair actually had nerves; it would feel just like going to the dentist’s office.  They would have to knock everyone out; it would be like…pulling teeth