Term | Definition |
alopecia | the technical term for hair loss |
alopecia arerata | the sudden falling out if hair in patches or spots |
alopecia prematura | hair loss that occurs before middle age |
alopecia senilis | hair loss occurring in old age |
alopecia syphilitica | Hair loss as a result of syphilis |
amino acids | the building blocks or units of structure in protein |
anagen phase | growth phase in the hair cycle |
androgenic alopecia | hair loss that occurs as a result of genetics, age, and hormonal changes; male pattern baldness |
arrector pili | involuntary muscle fiber attached to the follicle |
canities | technical term for grey hair |
carbuncle | the result of an acute, deep-seated bacterial infection in the subcutaneous tissue |
catagen phase | transition phase of the hair growth cycle |
cortex | middle layer of the hair |
cowlick | tuft of hair that stands straight up |
cuticle | outermost layer of the hair shaft |
dermal papilla | small, coned-shaped elevation located at the base of the hair follicle that fits into the hair bulb |
disulfide bond | aka sulfur bond; a type of chemical cross bond found in the cortex |
end bonds | aka peptide bonds; chemical bonds that join amino acids end to end |
eumelanin | melanin that gives brown and black color to hair |
follice | tubelike depression in the skin that contains the hair root |
folliculitis barbae | aka barber's itch; bacterial infection of the hair follicles with inflamed pustules in the bearded areas. |
furnucle | acute bacterial infection of the hair follicle, producing constant pain. aka boil |
hair bulb | club-shaped structure that forms the lower part of the hair root |
hair density | the amount of hair per square inch of scalp |
hair elasicity | the ability of the hair to stretch and return to its original length |
hair porosity | the ability for the hair to absorb moisture |
hair root | the part of the hair that is encased in the hair follicle |
hair shaft | the part of the hair that extends beyond the skin |
hair stream | hair that flows in the same direction |
hair texture | measures the diameter of the hair strand. fine, medium, coarse. |
hydrogen bond | a physical side bond in the hair cortex |
hypertrichosis | a condition of abnormal hair growth |
keratin | the protein of which hair is formed |
lanugo | vellus hair |
malassezia | fungus that causes dandruff |
medulla | center of the hair shaft |
pediculosis captis | head lice |
peptide bonds | end bonds; chemical bonds that join amino acids end to end |
pheomelanin | melanin that gives red to blonde color to hair |
pityriasis capitis simplex | dry dandruff type |
pityriasis steatoides | waxy/greasy dandruff type |
polypeptide chain | long chain of amino acids linked by peptide bonds |
primary terminal hair | short, thick hairs that grow on the eyebrows and lashes |
pseudofolliculitis barbrae | chronic inflammatory form of folliculitis known as "razor bumps" resembling folliculitis papules and pustules; generally accepted to be caused by ingrown hairs |
salt bond | a physical side bond within the hair cortex |
secondary terminal hair | long hair found on the scalp, beard, chest, back and legs |
side bonds | aka cross bonds; hydrogen, salt and sulfur bonds in the cortex |
sycosis vulgaris | chronic bacterial infection of the bearded areas of the face |
telogen phase | resting phase of the hair growth cycle |
tinea | technical term for ringworm |
tinea capitis | ringworm of the scalp |
tinea favosa | ringworm characterized by dry, sulfur-yellow crusts on the scalp |
tinea sycosis | ringworm of the bearded areas on the face |
trichology | the science of dealing with the hair, its diseases, and its care |
vellus | soft, downy hair that apprears on the body |
wave pattern | amount of movement in the hair strand. straight, wavy, curly, and coiled |
whorl | hair that grows in a circular pattern |