This type of overlapping arrangement is called imbrications. The cuticle may or may not completely surround the hair shaft, and normally the imbrications lie flat and close together. If you slide your fingers along dry hair from the end of the shaft to the scalp, the hair will feel sticky or rough. Because of this arrangement and the density of the cells, this outer layer forms a very effective shield for the inner part of the hair. It has been observed that the hair is the least destructible part of the body and the last of the human tissues to decay.
Alkali chemicals penetrate the cuticle and damage it to some extent.
The Inner part of the hair. This is the main section of the hair, and it is here that we find the pigment granules that give your hair its color. The natural coloring matter is contained in this second layer, and shows through the outer layer to give the hair its tones of brown, red, black, yellow, gray or white. When we change the natural color of hair, it is the color granules within the cortex that we change. Here also are the structures that give your hair its shape.