The hair cuticle is the outermost layer of the hair shaft, essentially forming a protective barrier around the hair. Here are some key points about the hair cuticle:
Structure
The cuticle is made up of overlapping, scale-like cells that lay like roof shingles. These scales, or cuticle cells, are primarily composed of keratin, the same protein that makes up the bulk of the hair.
Function
Its primary role is to protect the inner layers of the hair (cortex and medulla) from external damage, including environmental stressors like UV radiation, heat, and pollutants. When the cuticle is intact and smooth, it helps to retain moisture and nutrients within the hair shaft, contributing to its strength and shine.
Behavior
The cuticle can open and close due to various factors like heat, humidity, and toxins in textiles. When the cuticle opens, it exposes the inner layers of the hair to damage.