Hair Science and Structure Flashcards

How does humidity affect hair with high porosity?

Answer: It causes the hair to absorb moisture and swell, leading to frizz

Highly porous hair readily absorbs moisture from humid air through its open cuticle. This causes the hair shaft to swell unevenly, resulting in frizz and loss of style.

What is the cortex primarily composed of?

Answer: Elongated keratin protein chains arranged in bundles

The cortex is made up of elongated keratin protein chains (polypeptide chains) arranged in a coiled-coil structure and bundled into fibrils. These provide strength and elasticity.

What type of bond is a peptide bond in hair?

Answer: A permanent chemical bond that forms the backbone of protein chains

Peptide bonds are strong chemical bonds that link amino acids together end-to-end to form the long polypeptide chains (protein chains) that make up keratin. They cannot be broken without destroying the hair.

What is the acid mantle?

Answer: The natural acidic coating on hair and skin with a pH of 4.5-5.5

The acid mantle is the natural protective film on the surface of the hair and skin, composed of sebum and perspiration. It has a pH of approximately 4.5-5.5 and helps protect against bacteria and environmental damage.

Grey or white hair results from what change in the follicle?

Answer: Decreased or absent melanin production by melanocytes

Grey and white hair result from a reduction or complete loss of melanin production by melanocyte cells in the hair follicle. Without pigment, the hair appears grey or white.

What is hair elasticity and why is it important to test before chemical services?

Answer: The hair's ability to stretch and return without breaking; it indicates internal bond strength

Elasticity is the hair's ability to stretch and return to its original length without breaking. It reflects the condition of the cortex and its internal bonds. Poor elasticity indicates weakened bonds and a higher risk of damage from chemical services.