Ch 07 Vocabulary Hair and Scalp Properties Flashcards
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form the building blocks of protein; link together end to end like pop beads by strong, chemical peptide bonds (end bonds) to form the polypeptide chains that comprise proteins
amino acids
also known as the growth phase; hair phase during which new hair is produced
anagen phase
brief transition period between the growth and resting phases of a hair follicle; signals the end of the growth phase
catagen phase
small involuntary muscle in the dermis that attaches to the hair follicle; contraction of the muscle causes hair to stand, causing goose-bumps
arrector pilli muscle
five elements – carbon, oxygen, hydrogen, nitrogen, and sulfur – that make up human hair, skin, tissue, and nails
COHNS elements
fibrous protein layer of the hair; responsible for the strength, elasticity, and color of hair
cortex
hair that grows straight up or at a different angle than the other hair; usually more noticeable at the crown
cowlick
amino acid with a sulfur (S) atom that joins together two peptide strands
cysteine
cone-shaped elevation found at the base of the bulb
dermal papilla
strong chemical side bond that joins the sulfur atoms of two neighboring cysteine amino acids to create one cysteine, which joins together two polypeptide strands like rungs on a ladder
disulfide bond
consists of brown and black pigment and is the predominant pigment in black and brunette hair
eumelanin
found at the base of the follicle; has a bulb shape and contains living cells that will form the hair strand
hair bulb
outermost layer of hair; formed from cells that resemble shingles on a roof; protects cortex
hair cuticle
measures the number of individual hair strands on 1 square inch (2.5 square centimeters) of scalp
hair density
ability of the hair to stretch and return to its original length without breaking
hair elasticity
tube-like structure in the skin or scalp that surrounds the hair root and anchors the hair in the skin
hair follicle
refers to ability of the hair to absorb moisture
hair porosity
part of the hair located below the surface of the epidermis
hair root
part of the hair that projects above the epidermis
hair shaft
hair flowing in the same direction, resulting from follicles sloping in the same direction.
hair stream
thickness or diameter of an individual hair strand
hair texture
weak physical cross-link side bond that is easily broken by water or heat
hydrogen bond
fibrous protein of cells that is also the principal component of skin, hair and nails
keratin
process by which newly formed cells in the hair bulb mature, fill with keratin, move upward, lose their nucleus, and die
keratinization
bonds created when disulfide bonds are broken by hydroxide chemical hair relaxers
lanthionine bonds
short, fine hair that covers a fetus and generally sheds within a few weeks of birth
lanugo hair
innermost layer found in coarse hair and beard hair; know as hair’s pith or core; absent in fine hair
medulla
tiny grains of pigment in the cortex that give natural color to the hair
melanin
also known as an end bond; chemical bond that joins amino acids to each other, end-to-end, to form a polypeptide chain
peptide bond
yellow to red pigment found in natural blonde to red shades of hair
pheomelanin
long chain of amino acids linked by peptide bonds
polypeptide chain
weak physical cross-link side bond between adjacent polypeptide chains that is broken by changes in pH
salt bond
also known as oil glands; glands connected to hair follicles; secrete sebum
sebaceous glands
fatty or oily secretion that lubricates the skin and preserves the softness of the hair
sebum
bonds that cross-link polypeptide chains and are responsible for the extreme strength and elasticity of human hair; account for about one-third of hair’s overall strength
side bonds
also known as resting phase; the final phase in the hair cycle that lasts until the fully grown hair is shed
telogen phase
long, coarse, pigmented hair found on the scalp, legs, arms, and body
terminal hair
scientific study of hair and its diseases and care
trichology
short, fine, unpigmented hair that appears on the body, often referred to as peach fuzz. It is typically less than one-third inch long (approximately 1 centimeter) and can appear anywhere on the skin apart from the palms, soles, and lips
vellus hair
amount of movement or shape of the hair strand; described as straight, wavy, curly, or coily
wave pattern
occurs when hair leaves the follicles at an angle; hair grows in a circular pattern on the crown of the head
whorl