ch.11 properties of hair and scalp

trichology

scientific study of hair, its diseases and care

trichos

greek word means hair

integumentary system

hair, skin, nails and glands

hair root

hair located below surface of epidermis

follicle

pocket/tibe like depression in scalp of skin, contains hair root

originating in hair follicles hair is composed of protein that grows from cells

hair bulb

thickened, club like structure, forms at lower part of hair root

dermal papillae

small, cone shaped area located at base of hair follicles, fits into hair bulb

contains blood and nerve supply, provides nutrients for hair growth

arrector pili

small, involuntary muscle fiber at base of hair follicle

sebum

oil substance secreted by sebaceous gland, lubricates hair and skin

amino acids

body naturally produces 11 of the 20 that make up hair

units of structure build protein are joined together end to end like beads

hair cuticle

outermost layer of hair, creates shine and smooth, silky feel to healthy hair

protects hair from penetration prevents damage to hair fibers

cortex

cuticle layers overlap to protect

fibrous protein core formed by elongated cells containing melanin

changes like oxidation haircoloring, wet setting, chemical processes take place here

keratinized protein

hair shaft that emerges from scalp is a non living fiber composed of keratin protein, aprox 90% protein

COHNS elements

carbon, oxygen, hydrogen, nitrogen, and sulfur

polypeptide

long chains of amino acids linked by peptide bonds

proteins

substances comprised of long, coiled, complex polypeptides made of amino acids

side bonds

hydrogen, salt, and disulfide bonds that link chains of amino acids together

hydrogen bond

physical side bond easily broken by water and heat

broken by wetting hair with water and reformed when dries

salt bond

weak, physical, cross-link side bond between adjacent polypeptide chains broken by changes in pH

disulfide bond

permanent waving and hair relaxers change the shape of hair by chemically altering

lanthionin bond

hydroxide relaxers break disulfide bonds and convert to lanthionine bond

melanin

natural hair color is a result of this pigmemt

eumelanin

provides brown or black color to hair

pheomelanin

provides red, gingers, yellows to hair

hair stream

refers to the shape of hair strand

straight, wavy, curly, coiled

curly hair

oval is cross-section shape of curly hair

vellus hair

also known as lanugo hair

short, fine, unpigmented, and downy

growth cycles of human hair

anlagen, catchen, and telogen

anagen phase

phase which new hair is produced

telogen phase

resting phase or final phase of hair cycle, lasts until fully grown hair is shed

alopecia areata

sudden falling out of hair in round patches or baldness in spots

alopecia universalis

complete loss of all body hairp

postpartum alopecia

temporary hair loss experienced at end of pregnancy

canities

technical term for gray hair

hypertrichosis

condition of abnormal hair growth of terminal hair

trichoptilosis

technical term for spilt ends

trichorrhexis nodosa

condition that is characterized by brittleness and the formation of nodular swellings along the hair shaft

monilethrix

technical term for beaded hair

pityriasis

medical term for dandruff

fragilitas crinium

technical term for brittle hair

malassezia

a fungus resulting in dandruff

pityriasis steatoides

severe type of dandruff characterized by an accumulation of greasy or waxy scout skills, mixed with sebum

seborrheic dermatitis

severe form of dandruff accompanied by redness and inflammation

tinea

medical term for ringworm, itching, scales, circular lesions

tinea barbae

scalp disorder characterized by dry, sulfur - yellow, cup - like crust on the scalp

scabies

a highly contagious skin disease cased by a parasite called a mite

pediculosis capitis

infestation of hair and scalp with lice

furuncle

acute localized bacterial infection of hair follicle constant paint

texture

thickness or diameter of the individual hair strand

fine, medium, coarse

coarse hair

largest diameter, more processing

density

number of hair strands on one sq inch of scalp

thin, medium, thick

porosity

moisture absorption of hair

low, average, high

low requires more alkaline solution

elasticity

ability of hair to stretch and return to its original length without breaking

hair stream

hair flowing in the same direction, the result s of follicles sloping in the same direction

emollients

dry hair and scalp should be treated with products that contain moisturizers and emollients