Hair and Scalp Properties Flashcards

Vocabulary flashcards covering hair growth cycles, body hair types, scalp conditions, hair growth patterns, and analysis properties based on the lecture notes.

Anagen Phase

The growth phase of the hair cycle where new hair is produced and cells are created faster than any other cell in the body; accounts for about $90\%$ of scalp hair at any time and lasts $2\text{ to }6\,\text{years}$ (up to $10\,\text{years}$).

Catagen Phase

The brief transition period between growth and resting phases lasting $1\text{ to }2\,\text{weeks}$, during which the follicle canal shrinks, detaches from the dermal papilla, and the hair bulb disappears to form a rounded club; accounts for less than $1\%$ of scalp hair.

Telogen Phase

The final resting phase of the hair growth cycle lasting $3\text{ to }6\,\text{months}$, where hair either sheds or remains until pushed out by new growth; accounts for a little less than $10\%$ of scalp hair with normal shedding of $50\text{ to }100\,\text{hairs per day}$.

Lanugo Hair

Short, fine hair that covers a fetus and generally sheds within a few weeks of birth.

Vellus Hair

Short, fine, unpigmented body hair (peach fuzz) typically less than $\frac{1}{3}\,\text{inch}$ (approximately $1\,\text{cm}$) long, lacking sebaceous glands, that helps with perspiration evaporation and body temperature regulation.

Terminal Hair

Long, coarse, pigmented hair found on the scalp and body that may contain a medulla and can grow up to $3\,\text{feet}$ long.

Scalp Hair Growth Rate

The average growth rate for healthy scalp hair, which is about $0.5\,\text{inch}$ ($1.25\,\text{centimeters}$) per month; it grows rapidly between the ages of $15\text{ and }30$ and slows sharply after $50$.

Dry Hair and Scalp

A hair and scalp condition caused by inactive sebaceous glands and a lack of sebum, resulting in dull, dry, and lifeless hair; treated with moisturizers and emollients while avoiding frequent shampooing, strong soaps, detergents, and high alcohol content products.

Oily Hair and Scalp

A hair and scalp condition caused by overactive sebaceous glands, best managed by using shampoos that return the scalp to its natural pH, avoiding harsh products, and thoroughly rinsing.

Hair Stream

A hair growth pattern where hair flows in the same direction due to follicles sloping in the same direction; two hair streams flowing in opposite directions create a natural part.

Whorl

A hair growth pattern that occurs when hair leaves the follicles at an angle, causing the hair to grow in a circular pattern.

Cowlick

A hair growth pattern where hair grows straight up or at a different angle than surrounding hair, usually most noticeable at the crown.

Hair Texture

An element of hair analysis describing strand thickness, categorized by whether hair looks more like thread (fine) or yarn (coarse).

Hair Density

An element of hair analysis measured by how easily the scalp is seen through the hair, categorized as low/thin density (scalp easily visible) or high/thick density (scalp not easily visible).

Hair Porosity

The hair's ability to absorb moisture, evaluated on dry hair across four areas (front hairline, temple, crown, nape) by sliding fingers from end to scalp; results range from low porosity (smooth, compact, dense, hard cuticle) to porous or highly porous (rough, dry, or breaking).

Hair Elasticity

The hair's ability to stretch and return to its original length without breaking, which reflects the strength of side bonds in the cortex.

Average Hair Elasticity

A condition where wet hair stretches between $30\%\text{ to }50\%$ of its length and returns without breaking, while dry hair stretches about $20\%$ of its length.

Low Hair Elasticity

A condition where hair feels brittle, breaks easily, and fails to hold curls from wet setting, thermal styling, or perms due to weak side bonds from overprocessing or thermal damage; requires chemical solutions with a lower pH.