Anatomy, Physiology, and Skin Structure
What to know
Candidates must know the layers of the skin (epidermis, dermis, subcutaneous), the appendages (hair follicle, sebaceous gland, sweat gland, nail), and the functions of skin (protection, sensation, heat regulation, excretion, secretion, absorption). The epidermis is the outer protective layer; the dermis contains blood vessels, nerves, and glands; the subcutaneous layer stores fat. Hair growth cycles-anagen (growth), catagen (transition), telogen (rest)-explain shedding and treatment timing.
Traps to watch
- Confusing sebaceous (oil) with sudoriferous (sweat) glands.
- Misidentifying the dermis as the outer layer-it is the second layer.
- Confusing arteries (carry blood away from the heart) with veins (return blood).
- Ignoring nerve endings and the arrector pili muscle that causes goosebumps.
- Forgetting that skin absorbs some chemicals-relevant to patch testing and product safety.
Rule of thumb
Epidermis = protection, dermis = structure and sensation, subcutaneous = cushion and insulation.
Worked example
A question asks which layer contains the hair follicle and sebaceous gland. The follicle originates in the dermis (with the bulb deeper), and the sebaceous gland attaches to the follicle-so the answer is the dermis, not the epidermis.