pH, Hair Care Product Knowledge, and Hair Theory

Vocabulary flashcards covering key terms and definitions regarding pH levels, hair care product formulations, and hair growth and structure theory.

Acidic Solution

A solution with a pH less than $7$ that contains more positive hydrogen ions than negative hydroxide ions.

Alkaline Solution

A solution with a pH greater than $7$ that contains more negative hydroxide ions than positive hydrogen ions.

Neutral Solution

A solution with a pH of $7$, such as distilled water, where the number of hydrogen ions equals the number of hydroxide ions.

pH Scale

A scale ranging from $0$ to $14$ used to measure how acidic or alkaline a substance is.

pH Meter

An instrument that provides the most accurate method of measuring pH.

pH Range of Hair, Skin, and Nails

The natural pH level range for hair, skin, and nails, which is $4.5$ to $5.5$.

pH-Balanced Product

A product formulated to fall within a pH range of $4.5$ to $5.5$.

Solution

A mixture of two or more kinds of molecules, evenly dispersed.

Suspension

A mixture of two or more kinds of molecules that has a tendency to separate when left standing.

Surfactant

A surface-active ingredient found in shampoos that removes oil from hair, consisting of lipophilic and hydrophilic parts.

Lipophilic

The oil-loving part of a surface-active agent.

Hydrophilic

The water-loving part of a surface-active agent.

Porosity

The ability of hair to absorb moisture, liquids, or chemicals.

Wet Hair Elasticity

The ability of healthy hair to stretch up to $50\%$ of its length without breaking when wet.

Rinses

Hair products that affect mostly the surface of the hair to close the cuticle and improve manageability, which can be detrimental if allowed to build up on hair.

Body-Building Conditioner

A conditioner that penetrates into the damaged hair shaft and deposits proteins into the cortex layer.

Hair Bulb

The structure at the base of the hair root that displays living cells when observed under a microscope.

Hair Follicle

The tube-like pocket or root sheath from which hair grows; its cross-sectional shape determines natural hair texture (e.g., round for straight hair, elliptical for tightly curled hair).

Papilla

A structure located at the bottom of the hair follicle that supplies nourishment to the germinal matrix; hair pulled out from the roots can grow back if it is not destroyed.

Cuticle

The outer covering of the hairstrand made up of overlapping layers of transparent scales.

Cortex

The middle layer of hair consisting of unique protein structures that give hair most of its pigment and strength (elasticity).

Sebum

A natural oil produced by sebaceous glands that helps protect the hair and skin from becoming too dry.

Acid Mantle

A protective layer formed on the skin and hair when sebum mixes with perspiration.

Arrector Pili

The involuntary muscle attached to the hair follicle that causes hair to stand on end when a person is scared or cold.

Anagen Stage

The active growing stage of hair growth.

Catagen Stage

A brief transitional stage of hair growth that lasts only a few weeks.

Telogen Stage

The resting stage of hair growth when the hair bulb has no attached root sheath.

Eumelanin

The type of melanin pigment that produces brown and black hair color.

Albinism

The total lack of pigmentation in the hair and skin.

Gray Hair Cause

A condition resulting from reduced color pigment in the cortex layer of the hair.