Anatomy and Physiology of the Skin
What the domain tests
Anatomy and physiology questions test skin layers, cell types, glands, hair follicles, and skin functions. You need to connect structure to treatment safety, such as why the epidermis has no blood supply and why deeper wounds need medical referral.
Core rules and concepts
- The epidermis is avascular and keratinized. Layers from deep to surface: basale, spinosum, granulosum, lucidum (palms and soles), corneum.
- Keratinocytes produce keratin; melanocytes produce melanin; Langerhans cells participate in immunity; Merkel cells are sensory.
- The dermis contains collagen, elastin, fibroblasts, blood vessels, nerves, and glands. The papillary layer is superficial; the reticular layer is deeper.
- The hypodermis is subcutaneous fat that insulates and cushions.
- Sebaceous glands secrete sebum into hair follicles; eccrine sweat glands cool the body; apocrine glands are scent-related.
- Skin functions include protection, sensation, thermoregulation, vitamin D synthesis, and excretion.
Worked example
A client has a red, painful area after a hot towel, with no blister. Reasoning: this suggests a superficial epidermal injury. Stop the service, cool the area, avoid active ingredients, and refer if blistering, widespread pain, or signs of infection appear. Do not treat a burn as just sensitivity.
Traps that cost marks
Saying the epidermis contains blood vessels; confusing sebaceous and sweat glands; placing melanocytes only in the dermis; forgetting that the acid mantle and barrier live in the stratum corneum.