Scientific Concepts: Infection Control, Anatomy and Physiology, Chemistry
What this domain really tests
Scientific Concepts looks like three subjects bolted together, but the exam uses them the same way: to check that you can protect the client, describe the body you work on, and predict how a product will behave. Expect vocabulary-matching items and short scenario questions.
Infection control
Know the ladder: cleaning (soap and water, removes debris and many microbes), disinfection (an EPA-registered, hospital-grade product that destroys most pathogens on nonporous surfaces), and sterilization (destroys all microbial life including spores, and is not achieved by a salon jar). Implements must be cleaned, dried, fully immersed, and left for the label's contact time. Traps: topping off a dirty jar, calling a quat solution a sterilant, and forgetting that porous items (towels, cotton, wooden sticks, files without a removable surface) cannot be disinfected and are single-use. Also know Standard Precautions, the blood-spill sequence, and SDS sheets.
Anatomy and physiology
Name the cranial bones, the muscles of the face and scalp (frontalis, temporalis, occipitalis, masseter), the trigeminal and facial nerves, and the temporal and facial arteries. Questions love to swap a muscle for a nerve or an artery for a vein.
Chemistry
Use the pH scale fluently: below 7 acid, 7 neutral, above 7 alkaline; hair sits near 4.5–5.5. Know surfactants, solutions, suspensions, emulsions, and oxidation-reduction as it applies to color and neutralizers.
Rule of thumb
If you cannot disinfect it, you cannot reuse it. When a stem mentions blood or an unknown skin condition, stop, glove, disinfect with a tuberculocidal product for the full label time, and discard porous items.