Chapter 11 - Properties of the Hair and Scalp

also know 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.

technical term for gray hair; result from the loss of the hair's natural melanin pigment.

inflammation of the subcutaneous tissue caused by staphylococci; similar to a furuncle but larger.

the brief transition period between the growth and resting phases of a hair follicle. it signals the end of the growth phase.

the five elements - carbon, oxygen, hydrogen, nitrogen, and sulfur - that make up human hair, skin, tissue, and nails.

middle layer of the hair; a fiberous protein core formed by elongated containing melanin pigment.

tuft of hair that stands straight up.

an amino acid joined with another cysteine amino acid to create cystine amino acid.

an amino acid that joins together two peptide strands.

strong chemical side bond that joins the sulfur atoms of two neighboring cysteine amino acids to create one cystine, which joins together two polypeptide strands like rungs on a ladder.

technical term for brittle hair

boil; acute, localized bacterial infection of the hair follicle that produces constant pain.

lowest part of the hair strand; the thickened, club-shaped structure that forms the lower part of the hair root.

outermost layer; consisting of a single, overlapping layer of transparent, scale-like cells that look like shingles on a roof.

the number of individual hair strands on 1 sqaure inch (2.5 square centimeters) of scalp.

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

the tube-like depression or pocket in the skin or scalp that contains the hair root.

ability of the hair to absorb moisture.

the part of the hair located below the surface of the epidermis.

the portion of hair that projects above the epidermis

hair flowing in the same direction, resulting from follicles sloping in the same direction.

thickness or diameter of the individual hair strand.

spiral shape of a coiled protein created by polypeptide chains that intertwine with each other.

a weak, physical, cross-link side bond that is easily broken by water or heat.

easily absorbs moisture; in chemistry terms, capable of combining with or attracting water (water-loving).

naturally resistant to being penetrated by moisture.

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.

process by which newly formed cells in the hair bulb mature, fill with keratin, move upward, lose their nucleus, and die.

the bonds created when disulfide bonds are broken by hydroxide chemical hair relaxers after the relaxer is rinsed from the hair.

naturally occurring fungus that is present on all human skin, but is responsible for dandruff when it grows out of control.

innermost layer of the hair that is composed of round cells; often absent in fine and naturally blond hair.

technical term for beaded hair.

infestation of the hair and scalp with head lice.

also known as an end bond; chemical bond that joins amino acids to each other, end to end, to form a polypeptide chain.