What We Do See: The Shaft
The hair shaft is made up of dead, hard protein called keratin in three layers. The inner layer is called the medulla and may not be present. The next layer is the cortex and the outer layer is the cuticle.
We have a very special relationship with our hair and are always surprised, even shocked, to learn that the part we see which goes to make up our precious head of hair is in fact, biologically dead. Furthermore, it receives no further assistance from the root which created it. However, the hair fibre does have an absolutely remarkable structure.
The hair shaft is made up of dead, hard protein called keratin in three layers. The inner layer is called the medulla and may not be present. The next layer is the cortex and the outer layer is the cuticle. The cortex makes up the majority of the hair shaft. The cuticle is formed by tightly packed scales in an overlapping structure similar to roof shingles. Most hair conditioning products attempt to affect the cuticle. There are pigment cells that are distributed throughout the cortex and medulla giving the hair it's characteristic color.
