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predominate pigment found in brown and black hair
what is eumelanin
weak physical cross link side bond between 2 polypeptide chains that is broken by ph
what is a salt bond
study of hair including diseases and care
what is trichology
amount of movement or shape of the hair strand, straight,wavy,coily etc
what is wave pattern
fatty or oily secretion that lubricates the skin and preserves the softness of hair
what is sebum
these 2 things are growth patterns that develop on the head usually on the crown of the head. 1 is circular and the other usually grows in the opposite direction of the hair around it.
what is a cowlick and a whorl
weak physical crosslink side bond that is easily broken by heat or water
what is hydrogen bond
hair flowing in the same direction, resulting in follicles sloping in the same direction
what is hair stream
cone shaped elevation found at the base of the bulb
what is the dermal papilla
long coarse pigmented hair found on the scalp, legs, arm and body
what is terminal hair
found at the base of the follicle, has a bulb shape and contains living cells that will form the hair strand
what is the hair bulb
short fine hair that covers a fetus and generally sheds within a few weeks of birth
what is lanugo hair
refers to the ability of the hair to absorb moisture
what is hair porosity
aka end bond. chemical bond that joins amino acids together to form a polypeptide chain
what is a peptide bond
thickness or diameter of an individual hair strand
what is hair texture
yellow to red pigment found in natural blonde to red shades of hair
what is pheomelanin
form the building blocks of protein, link end to end by peptide bonds to form polypeptide chains which comprise proteins
what are amino acids
innermost layer found in coarse hair and beard hair, absent if fine hair
what is the medulla
part of the hair that projects above the dermis
what is the hair shaft
signals the end of the growth phase. brief transition period between growth and resting phases
what is the catagen phase
responsible for the strength, elasticity and color of hair.
what is the cortex
short fine unpigmented hair often referred to as peach fuzz. typically is less than a 3rd of an inch long and can appear anywhere except palms,soles and lips
what is vellus hair
outermost layer of the hair, protects the cortex, cells resemble shingles on a roof
what is the hair cuticle
fibrous protein of cells that is also the principal component of hair, skin and nails
what is keratin
part of the hair located below the surface of the epidermis
what is the hair root
tiny grains of pigment that give natural color to the hair
what is melanin
measures the number of individual hair strands in 1 square inch of scalp
what is hair density
bonds created when disulfide bonds are broken by hydroxide chemical hair relaxers
what are lanthionine bonds
aka growth phase.hair phase which new hair is produced
what is anagen phase
amino acid with a sulfur atom that joins together 2 peptide strands
what is cysteine
small involuntary muscle in the dermis that attaches to the hair follicle. causes goose bumps
what is arrector pili muscle
long chain of amino acids linked by peptide bonds
what are polypeptide chains
5 elements that make up human hair,skin,tissues and nails-
what is COHNS- carbon, oxygen, hydrogen,nitrogen and sulfur
bonds that cross link polypeptide chains and are responsible for the extreme strength and elasticity of human hair. accounts for a third of hairs overall strength
what are side bonds
the ability of the hair to stretch and return
what is hair elasticity
aka resting phase. the final phase in the hair cycle that lasts until the fully grown hair is shed
what is telogen phase
strong chemical side bond that joins the sulfur atoms of 2 cysteine amino acids to create 1 cysteine
what is a disulfide bond
process by which newly formed cells in the hair bulb mature, fill with keratin, move upward, lose their nucleus and die
what is keratinization
tube like structure in the skin or scalp that surrounds the hair root and anchors the hair in the skin
what is the hair follicle
connected to hair follicles and secrete sebum
what are the sebaceous glands