ND Barber flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Hair follicle bulge

The swelling on the outer root sheath near the arrector pili insertion that houses epithelial stem cells; it supplies cells for follicle regeneration during each new growth cycle.

Anagen phase

The active growth stage of the hair cycle, lasting roughly two to seven years on the scalp; most scalp hairs are in this phase at any given time.

Catagen phase

A short transitional stage of about two to three weeks when growth stops, the follicle regresses upward, and the lower portion begins to break down.

Telogen phase

The resting stage lasting around three months, during which the club hair remains in the follicle before being shed in the exogen phase.

Disulfide bond

A strong chemical link between cysteine amino acids in the hair cortex; it gives hair tensile strength and is broken by relaxers and perms.

Eumelanin and pheomelanin

The two melanin pigments produced in the hair bulb; eumelanin yields brown to black shades and pheomelanin yields red and yellow tones.

Alopecia areata signs

Well-demarcated round patches of hair loss with smooth skin and short exclamation-point hairs at the edges; autoimmune, so refer rather than treat cosmetically.

Traction alopecia

Marginal hair loss at temples and nape caused by sustained tension from tight braids, weaves, or ponytails; early recognition and tension reduction prevent permanent loss.

Scarring alopecia

Hair loss in which follicular openings are absent and the skin appears shiny or scarred; irreversible and requiring dermatologic referral before any chemical service.

Tinea capitis signs

Scalp fungal infection showing scaling, hair broken at scalp level, black-dot patches, and possible lymph node swelling; treat medically, not with cosmetic products.

Patch test purpose

A screening step applying a small amount of product 24 to 48 hours before service to detect allergic contact dermatitis, especially to oxidative dyes.

Strand test purpose

A test on a sample of the client's own hair to predict processing time, color lift, and structural integrity before committing to a full chemical service.

Developer volume meaning

The concentration of hydrogen peroxide in an oxidative product; 10 volume deposits, 20 volume lifts about one level, and 30 to 40 volume lifts more with greater risk.

No-lye relaxer chemistry

A relaxer using guanidine hydroxide formed from calcium hydroxide and an activator; it straightens hair while producing less scalp irritation than sodium hydroxide formulas.

Neutralizing step

The post-perm process that rebuilds disulfide bonds and restores acidic pH; incomplete neutralization leaves hair over-elastic, limp, and prone to breakage.

Taper versus fade

A taper shortens hair only at the perimeter and leaves a visible weight line; a fade blends gradually from short to long with no discernible line.

Para-phenylenediamine

The primary sensitizer in permanent oxidative hair dye; allergy is lifelong and cross-reactivity occurs with related aromatic amines, so patch testing matters.

Black henna risk

Products marketed as black henna often contain added para-phenylenediamine to darken the stain, raising the risk of severe allergic sensitization.

Ammonium persulfate

The oxidizing booster in bleach powders; it is a respiratory and skin irritant, so mixing should occur in ventilated areas with minimal inhalation.

Thioglycolate function

Ammonium thioglycolate reduces disulfide bonds in perms and depilatories; it is incompatible with oxidative dye in the same session.

Telogen effluvium trigger

Diffuse shedding appearing about two to three months after illness, surgery, childbirth, or severe dieting; identifying the trigger timeline guides the history.

Iron and hair shedding

Iron deficiency is a common reversible contributor to diffuse hair loss; ferritin and hemoglobin interpretation and treatment belong to the clinician, not the barber.

Counseling scope limit

Barbers may give general wellness and aftercare information but must not diagnose deficiency, prescribe supplements, or interpret laboratory results for clients.

Informed consent

Disclosing foreseeable risks of a chemical service such as breakage, allergic reaction, and unpredictable color, then documenting the client's agreement before proceeding.

Client service record

Documentation of service date, products and batch, patch and strand test results, and any adverse reaction; supports continuity and defends against later disputes.

Scope of practice

The legally permitted services defined by the state licensing board; cosmetic services only, with suspected disease referred to a physician.

Blade number rule

Clipper blade and guard numbers increase in eighth-inch increments; a number one leaves about one-eighth inch and a number four about one-half inch.

Cross-checking haircut

Cutting a section a second time perpendicular to the original section to verify balance, symmetry, and even length distribution.

Razor cutting effect

Slicing the cuticle with a razor softens texture and adds movement but increases porosity; avoid on fine or previously lightened hair.

Porosity assessment

A practical check of how quickly hair absorbs and releases water and product; high porosity feels rough and dries fast, low porosity resists moisture.

Elasticity test

Stretching a wet strand to judge structural integrity; normal hair extends about thirty percent and recoils, while over-processed hair stretches and fails to return.

Protein versus moisture

Protein treatments temporarily fill cortical gaps and strengthen, while moisture treatments restore hydration; excess protein on low-porosity hair causes stiffness and snapping.