NIC Cosmetology Written (Theory) ExamScientific ConceptsHard
A cosmetologist is performing a chemical peel service. The peel uses an alpha hydroxy acid (AHA), which works by dissolving the intercellular cement that binds cells together. Which layer of the epidermis is primarily targeted by this action to achieve exfoliation?
- AStratum spinosum
- BStratum corneum
- CStratum granulosum
- DStratum lucidum
Show answer & explanationAnswer & explanation
Correct answer: B. Stratum corneum
Alpha hydroxy acids (AHAs) primarily work on the stratum corneum, the outermost layer of the epidermis, by loosening the desmosomes (intercellular cement) that hold dead skin cells together. This action facilitates exfoliation and promotes cell turnover.
Why the other options are wrong
- A. The stratum spinosum is primarily responsible for cell cohesion and strength, deeper than the primary target of AHA exfoliation.
- C. The stratum granulosum is involved in keratinization and lipid production, but not the primary target for surface exfoliation by AHAs.
- D. The stratum lucidum is present only in thick skin (palms and soles) and is not the primary target for general facial exfoliation by AHAs.
Stratum Corneum
The outermost layer of the epidermis, composed of flattened, dead keratinocytes (corneocytes) that provide a protective barrier against environmental damage and water loss.
- Outermost epidermal layer
- Composed of dead, flattened cells (corneocytes)
- Provides barrier protection
- Targeted by exfoliants like AHAs
Memory trick: Come Let's Get Sun Burned (Corneum, Lucidum, Granulosum, Spinosum, Basale)