Properties of Hair and Scalp

Trichology

the scientific study of hair, its diseases, and care

Asians tend to have

extremely straight hair

The catagen phase signals

the end of the growth phase

Hypertrichosis

is also known as hirsuites

The hair root and hair shaft

the two parts of a mature strand of human hair

Vellus

the type of hair that almost never has a medulla

When the living cells of hair form and begin their journey upward through the hair follicle

they mature in a process called keratinization

Tinea

the technical term for ringworm

To help minimize tangle in extremely curly hair when shampooing, you should use a detangling rinse

you should use a detangling rinse

Coarse hair

is stronger than fine hair

Alopecia areata

an autoimmune disorder that causes the affected hair follicles to be mistakenly attacked by a person's own immune system

During the anagen phase,

new hair is produced because new cells are actively manufactured in the hair

Cross-sections of hair can be

almost any shape

The cortex

the middle layer of the hair

The hair follicle

the tube-like depression or pocket in the skin or scalp that contains the hair root

Dandruff can easily be mistaken for dry scalp

for dry scalp

Vellus hair is also known as

lanugo hair

Sebum

the fatty or oily substance secreted by the sebaceous glands

Pityriasis

the technical term for dandruff

Helix

the term for the spiral shape for a coiled protein

Hair follicles are not found

on the soles of the feet

Pediculosis capitis

the infestation of the hair and scalp with head lice

Hair porosity

the ability of the hair to absorb moisture

The medulla

is composed of round cells

Congenital canities

exists at or before birth

The hair root

the part of the hair located below the surface of the epidermis

The arrector pilli muscle

is the small, involuntary muscle in the base of the hair follicle

Canities

the technical term for gray hair

Whorl

when hair leaves the follicles at an angle and forms patterns or streams on the head

For chemicals to penetrate a healthy cuticle hair layer,

they must have an alkaline pH

Finasteride

is an oral prescription medication for hair loss that is meant for men only

Trichorrhexis nodosa

the technical term for knotted hair

Peptide bonds

the strong, chemical bonds that join amino acids

Sebaceous glands

the oil glands in the skin that are connected to the hair follicles

Terminal hair

the long, coarse, pigmented hair found on the scalp, legs, arms, and bodies of males and females

The major elements that make up human hair are

are carbon, oxygen, hydrogen, nitrogen, and sulfur

A condition of abnormal growth of terminal hair in areas of the body that normally grow only vellus hair is

hypertrichosis

Characterized by itching, scales, and sometimes, painful circular leasions

tinea

A cowlick

a particular pattern of hair stream that is usually more noticeable on the front of the hairline in people with short, thick hair

Pheomelanin

the type of melanin that provides natural colors ranging from red and ginger to yellow and blond tones

The anagen phase

generally lasts from three to five years

The innermost layer of the hair and is composed of round cells

the medulla

Scalp massage

does not increase hair growth

Hair texture

classified as coarse, medium, or fine

By age 35, almost ________percent of both men and women show some degree of hair loss

40

The hair, skin, nails, and glands are part of

the integumentary system

Hair density

the measurement of the number of individual hair strands on one square inch (2.5 centimeters)

Fine hair

is more fragile than coarse or medium hair

Scutula

dry, sulfur-yellow, cuplike crusts on the scalp

Compared to hair with high porosity, chemical services performed on hair with low porosity

require more alkaline solutions

Bald men are commonly perceived as

less successful

Shaving, clipping, and cutting the hair on the head has

no effect on hair growth

A carbuncle is similar to a furuncle but

it is larger

Wet hair with normal elasticity will stretch up to _______ percent of its original length and return to that length

50

The hair bulb

is the lowest part of a hair strand

Scalp hair grows faster on women than on men

on women than on men

Areata totalis

total scalp hair loss

Hair is approximately ______ percent protein

90

Oily hair and scalp can be treated by properly washing with

a normalizing shampoo

The hair cuticle

the outermost layer of the hair

Scabies

a highly contagious skin disease caused by a parasite called a mite that burrows under the skin

The follicle canal shrinks and detaches from the dermal papilla

during the catagen phase

Fungus

current research confirms that dandruff is the result of this

Monilethrix

the technical term for beaded hair is monilethrix

Hydrogen bond

a weak, physical, cross-link side bond easily broken by water or heat

Because there are so many of them, salt bonds account for about __________ of the hair's overall strength

one third

The average growth of healthy scalp hair is

½ inch (1.25 centimeters) per month

Compared to pigmented hair, gray hair is

exactly the same

The dermal papilla

the structure of the hair root that contains the blood and nerve supply that provides the nutrients needed for hair growth

Malassezia

the naturally occurring fungus that causes the symptoms of dandruff when it grows out of control is malassezia