Scientific Concepts: Bacteriology, Anatomy, Chemistry, and Sanitation
What a candidate must know
Bacteriology. Bacteria are one-celled microorganisms classified by shape: cocci (round), bacilli (rod), spirilla (spiral). Groupings matter on exams - staphylococci form clusters (pus-producing), streptococci form chains, diplococci occur in pairs. Know the difference between pathogens and nonpathogens, the difference between local and systemic infection, and that bacterial spores are the toughest form to kill. Viruses (hepatitis B and C, HIV, herpes) do not respond to antibiotics; fungi cause tinea (ringworm) conditions; parasites include pediculosis (lice) and scabies.
Anatomy. Review the skull and face bones (frontal, parietal, temporal, occipital, zygomatic, maxilla, mandible) and the muscles of expression and mastication (frontalis, temporalis, occipitalis, masseter, zygomaticus, orbicularis oculi, mentalis, platysma). Pair the facial nerve (VII) with motor function and the trigeminal (V) with sensation. Trace blood from the common carotid to the internal/external carotid, superficial temporal, occipital, and facial arteries.
Chemistry. The pH scale runs 0–14; 7 is neutral, below 7 acidic, above 7 alkaline. Hair and skin sit around pH 4.5–5.5. Understand solutions, suspensions, and emulsions, surfactants, and oxidation–reduction (the basis of color and neutralizers).
Sanitation. Separate cleaning (soap and water), disinfection (EPA-registered hospital-grade disinfectant), and sterilization (kills all microorganisms including spores).
Traps
- Calling ringworm bacterial - it is fungal and contagious; refer it.
- Confusing disinfection with sterilization.
Rule of thumb
Each whole pH number is a tenfold change. A pH 3 solution is 1,000 times more acidic than pH 6 (three steps = 10 × 10 × 10).