Scientific Concepts: Anatomy, Physiology, Chemistry, and Infection Control
What this domain tests
The Scientific Concepts domain checks whether you can apply anatomy, physiology, chemistry, and infection control at the chair, not just recite definitions. Expect questions that link a client condition or product label to a safe decision.
Anatomy and physiology you will use
- Skin: epidermis (outer barrier), dermis (nerves, vessels, glands), subcutaneous layer; acid mantle around pH 4.5–5.5.
- Hair: follicle, bulb, dermal papilla; cuticle, cortex, medulla; growth stages anagen, catagen, telogen.
- Nails: plate, bed, matrix, lunula, cuticle; the matrix produces the plate, so trauma there can permanently alter growth.
Chemistry and infection control
The pH scale runs 0–14; alkaline products swell and soften hair, acids tighten the cuticle. Disinfection kills most pathogenic organisms on hard, nonporous surfaces; sterilization destroys all microbial life and is not a salon task. Use an EPA-registered hospital-grade disinfectant with bactericidal, virucidal, and fungicidal claims, and follow the label contact time. Standard precautions mean treat all blood and body fluids as infectious.
Worked example
A haircut client has a small bleeding nick. Stop the service, put on gloves, clean the area, apply an EPA hospital-grade disinfectant or a freshly mixed 1:10 bleach solution per label, and double-bag contaminated disposable items. Reason: bloodborne pathogens require a blood-spill response, not a simple surface wipe.
Traps
Calling a UV cabinet “sterilization”; skipping contact time; using disinfectant on porous files; confusing skin pH with product pH; assuming a visible clean surface is disinfected.