Chapter 11 properties of the hair and scalp terms

telogen phase

(resting phase) the final phase in the hair cycle that lasts until the fully grown hair is shed.

Tinea favosa

(tinea favus) fungal infection characterized by dry, sulfur-yellow, cup-like crusts on the scalp called scutula.

Keratin

A fibrous protein that grows from cells originating within the hair follicle.

Salt bond

A weak, physical, cross-link side bond between adjacent polypeptide chains. Salt bonds depends on PH, so they are easily broken by strong alkaline or acidic solutions.

hydrogen bond

A weak, physical, cross-link side bond that is easily broken by water or heat. Although individual hydrogen bonds are very weak, there are so many of them that they account for about one third of the hairs overall strength.

Hair elasticity

Ability of the hair to stretch and return to its original length without breaking.

androgenic alopecia

Also known as androgenetic alopecia; hair loss characterized by miniaturization of terminal hair that is converted to vellus hair; in men, it is known as male pattern baldness.

Hypertrichosis

Also known as hirsuties; condition of abnormal growth of hair, characterized by the growth of terminal hair in areas of the body that normally grow only vellus hair.

Cystine

An amino acid formed when 2 cysteine amino acids (with single sulfur) are joined by their sulfur groups or disulfide bond.

Cysteine

An amino acid with a sulfur atom (S) that joins together two peptide strands.

alopecia areata

Autoimmune disorder that causes the affected hair follicles to be mistakenly attacked by a person's own immune system; usually begins with one or more small, round, smooth bald patches on the scalp.

Side bonds

Bonds that cross-link the polypeptide chains together and are responsible for the extreme strength and elasticity of human hair.

oily hair

Caused by overactive sebaceous glands causing buildup of sebum.

alopecia universalis

Complete loss of body hair

dermal papilla

Dermal papillae. A small cone shaped elevation located at the base of the hair follicle that fits into the hair bulb.

Scutula

Dry, sulfur-yellow, cup-like crusts on the scalp in tinea favosa or tinea favus.

Dry hair and scalp should be treated with products that contain moisturizers and:

Emollients

anagen phase

Growth Phase, new hair is produced. Average growth of a healthy scalp is about 1/2(0.5)inch (1.25 cm) per month.

Trichology is the scientific study of

Hair and its diseases and care. Comes from the Greek word trichos (hair) and ology (the study of).

Extremely curly hair

Hair grows in long twisted spirals or coils

Whorl

Hair that forms in a circular pattern on the crown of the head

Coarse hair

Hair that has the largest diameter and usually requires more processing

Hydrophobic

Healthy hair with a compact cuticle layer is naturally resistant to being penetrated by moisture. (Doesn't love water)

lanthionine bonds

Hydrogen chemical hair relaxer break disulfide bonds and during rinsing convert them to...

Barbae folliculitis

Infected follicles or ingrown hairs from shaving or other hair removal methods such as waxing

carbuncle

Inflammation of the subcutaneous tissue caused by staphylococci; similar to a furuncle but larger.

terminal hair

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

Proteins

Long, coiled complex polypeptides made of amino acids.

hair bulb

Lowest part of a hair strand; the thickened, club-shaped structure that forms the lower part of the hair root.

cortex

Middle layer of the hair; a fibrous protein core formed by elongated cells containing melanin pigment. 90 percent of the total weight of the hair comes from the Cortex.

Fine hair

More fragile; easier to process

Medium hair

Most common hair texture; does not pose any problems or concerns

Malassezia

Naturally occurring fungus that is present on all human skin, but is responsible for dandruff when it grows out of control.

Average porosity

Normal hair

hair cuticle

Outermost layer of hair; consisting of a single, overlapping layer of transparent, scale-like cells that look like shingles on a roof.

Hair root

Part of the hair located below the surface of the epidermis ( outer layer of the skin).

Hydrophilic

Porous hair has a raised cuticle later that easily absorbs moisture ( loves water )

Keratinization

Process by which newly formed cells in the hair bulb mature, fill with keratin, move upward, lose their nucleus, and die.

Eumelanin

Provides natural dark brown to black color to the hair and is the dark pigment predominant in black and brunette hair.

alopecia totalis

Severe case of alopecia areata where balding occurs over the entire head

Pityriasis steatoides

Severe case of dandruff characterized by an accumulation of greasy or waxy scales mixed with sebum, that stick to the scalp in crusts.

vellus hair

Short fine unpigmented and downy hair that appears on the body

Helix

Spiral shape of a coiled protein created by polypeptide chains that intertwine with each other.

disulfide bonds

Strong, chemical, side bond that is very different from the physical side bond of a hydrogen bond or salt bond.

Monilethrix

Technical term for beaded hair

pityriasis capitis simplex

Technical term for classic dandruff; characterized by scalp irritation, large flakes, and itchy scalp.

Pityriasis

Technical term for dandruff; characterized by excessive production and accumulation of skin cells.

Canities

Technical term for gray hair; results from the loss of the hair's natural melanin pigment.

Trichorrhexis nodosa

Technical term for knotted hair; it is characterized by brittleness and the formation of nodular swellings along the hair shaft.

Trichoptilosis

Technical term for split ends

hair porosity

The ability of the hair to absorb moisture

catagen phase

The brief transition period between the growth and resting phases of a hair follicle. It signals the end of the growth phase.

Medulla

The innermost layer of hair composed of round cells; hair missing the medulla is fine or fragile.

Pheomelanin

The lighter pigment that provides natural colors ranging from red and ginger to yellow and blond tones.

Hair shaft

The portion of the hair that projects above the epidermis.

sebum

The sebaceous glands secrete a fatty or an oily substance called sebum. Sebum lubricates the skin.

Wave pattern

The shape of the hair strands; described as straight, wavy, curly, and extremely curly.

arrector pili muscle

The small, involuntary muscle in the base of the hair follicle.

Hair follicle

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

hair texture

Thickness or diameter of the individual hair strand

Melanin

Tiny grains of pigment in the cortex that give natural color to the hair.

cowlick

Tuft of hair that stands straight up

High porosity

When the cuticle is lifted and the hair is overly porous and takes color quickly

Low porosity

When the cuticle is tight and the hair is resistant, it is difficult for moisture or chemicals to penetrate.

Pseudofolliculitis barbae

a chronic inflammatory form of folliculitis known as "razor bumps" resembling folliculitis papules and pustules; generally accepted to be caused by ingrown hair

furuncle

boil; a painful nodule formed in the skin by inflammation originating in a hair follicle; caused by staphylococcosis

low elasticity

brittle and breaks easily

amino acids

building blocks of proteins. Units that are joined together end to end like pop beads.

Oily hair and scalp

caused by improper shampooing or overactive sebaceous gland resulting in oily hair

curly hair

flat

Hair stream

hair flowing in the same direction, resulting from follicles sloping in the same direction.

alopecia

hair loss

peduculosis capitis

head lice

Dry hair and scalp can be caused by

inactive sebaceous glands

Folliculitis

infections of the hair follicles

polypeptide chain

long chain of amino acids linked by peptide bonds.

sebaceous glands

oil glands of the skin connected to hair follicles.

wavy hair

oval cross section

tinea

ringworm

straight hair

round cross section

peptide bond

strong chemical bond that joins amino acids. Also known as end bond.

fragilitas crinium

technical term for brittle hair

postpartum alopecia

temporary hair loss experienced at the conclusion of a pregnancy

COHNS elements

the five elements- carbon, oxygen, hydrogen, nitrogen and sulfur- that make up human hair, skin, tissue, and nails.

hair density

the number of individual hair strands on 1 square inch (2.5 square centimeters) of scalp

ringed hair

variety of canities characterized by alternating bands of gray and pigmented hair throughout the length of the hair strand