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