Cortex (hair)

The cortex is the main bulk of the hair shaft, located between the cuticle and the medulla. It is responsible for the hair's strength, elasticity, and color. The cortex is made up of elongated cells called cortical cells, which are packed tightly together and aligned parallel to the length of the hair. These cells contain melanin, the pigment that gives hair its natural color.

Structure and Composition:

The cortical cells are held together by an intercellular cement substance. They are composed primarily of keratin, a fibrous protein rich in sulfur. The arrangement and composition of the keratin fibers within the cortex determine the hair's physical properties, such as its curl pattern and ability to withstand stretching. Different types of keratin and their arrangement within the cortex lead to variations in hair texture and behavior.

Melanin:

Melanin is produced by melanocytes located in the hair follicle and then transferred to the cortical cells. The type and amount of melanin determine the hair's shade. Eumelanin is responsible for brown and black hues, while pheomelanin contributes to red and blonde tones.

Importance:

The cortex is critical for various hair treatments and processes. Chemical treatments like perming, straightening, and coloring alter the structure of the cortex to achieve desired results. Damage to the cortex can lead to weakened, brittle hair that is prone to breakage. Understanding the structure and function of the cortex is essential for maintaining healthy hair and performing effective hair treatments.