National Occupational Competency Testing Institute (NOCTI) Cosmetology Practice Exam

When is hair likely to be resistant to chemicals in a hair treatment?

1. When the cuticle is damaged

2. When the cuticle is close to the cortex

3. When the hair is freshly washed

4. When the hair is thick

The correct answer is: When the cuticle is close to the cortex

Hair is likely to be resistant to chemicals in a hair treatment when the cuticle is close to the cortex. This is because the cuticle acts as a protective layer that surrounds the inner layers of the hair shaft, particularly the cortex, which is where most of the hair's strength and elasticity come from. If the cuticle is intact and closely bonded to the cortex, it can create a barrier that makes it more difficult for chemicals to penetrate the hair shaft effectively. When the cuticle is damaged, it can actually allow chemicals to penetrate more easily, leading to a lesser effect of treatment but potentially more harm to the hair. Similarly, freshly washed hair might have a softer cuticle, making it more susceptible to chemical interaction rather than resistant. Thickness does not inherently correlate with resistance; while thicker hair may have a denser cuticle, it does not guarantee that the chemicals will be effectively resisted, as other factors such as overall health and condition of the hair also play significant roles.