Anatomy and Physiology of Skin, Hair and Nails
What this domain covers
This domain gives the basic structure and function of skin, hair, and nails needed to perform services safely. The exam tests layers, growth stages, nail parts, and the reason behind safe practice.
Core rules and concepts
- Skin has three main layers: the epidermis, the dermis, and the subcutaneous layer. The epidermis is the outer protective layer; the dermis contains blood vessels, nerves, glands, and hair follicles.
- Skin protects the body, regulates temperature, senses touch, and produces vitamin D. It also absorbs some products, which is why patch tests matter.
- A hair has a follicle below the skin and a shaft above it. The shaft has a cuticle, cortex, and medulla. The cuticle is the outer protective layer.
- Hair growth has three phases: anagen (growth), catagen (transition), and telogen (rest). Hair does not grow faster because it is trimmed.
- The nail unit includes the nail plate, nail bed, matrix, lunula, cuticle, and free edge. The matrix produces the nail plate.
Worked example
Why should a manicurist push back the cuticle rather than cut it?
Reasoning: The cuticle seals the space between the nail plate and the skin and helps keep bacteria out. Cutting it can create a break in the skin and increase the risk of infection. The safe routine is to soften the cuticle with water or a cuticle softener, gently push it back with a sanitised tool, and trim only a hanging tag if salon policy allows. The reasoning links anatomy to infection control, which is what the exam rewards.
Traps that cost marks
- Confusing the epidermis with the dermis.
- Saying trimming makes hair grow thicker or faster.
- Treating the nail plate as living tissue that can be “fed” by polish.
- Cutting the cuticle deeply during manicure.