Anatomy, Physiology, and Professional Practices
Core Concepts
The skin has three main layers: epidermis, dermis, and subcutaneous tissue. The epidermis is avascular and includes the stratum corneum, the barrier; melanocytes produce melanin and influence phototype. The dermis contains collagen, elastin, blood vessels, nerves, sebaceous glands, and hair follicles. Sebaceous glands secrete sebum; sweat glands help regulate temperature. Understand the hair follicle and growth cycle, wound healing, and the inflammatory response. Facial anatomy includes bones, muscles of expression, nerves, and blood vessels; massage and product application should respect underlying structures and avoid pressure over the eyes, thyroid, and inflamed areas.
Physiology links body systems to skin: endocrine hormones affect sebum and pigmentation; circulation delivers oxygen and nutrients; lymphatics support drainage; the immune system mediates allergic and irritant reactions. Recognize signs of infection and systemic illness and refer rather than diagnose.
Professional practice covers scope of practice, ethics, informed consent, confidentiality, sanitation, communication, boundaries, and continuing education. Estheticians improve the appearance and condition of the epidermis; medical conditions, suspicious lesions, and deeper treatments require a physician or dermatologist. Keep records, respect client privacy, and avoid guarantees.
Traps
Questions often test that the epidermis has no blood vessels, that the dermis contains vessels and nerves, and that estheticians do not diagnose skin cancer. Another trap is confusing a muscle action with a bone landmark, or treating a client with a suspicious mole.
Worked Example
If a client points to an irregular, changing mole and asks you to treat or remove it, do not treat. Document the location and refer to a dermatologist. Continue only with services that avoid the lesion and remain within scope.