1
______ are attached to the hair follicle and produce an oily substance that lubricates the hair and skin
What is sebaceous glands
What phase of the hair growth cycle refers to the brief transition period between the hair follicle's growth and the resting phases?
What is the catagen phase
_________ measures the number of individual hair strands on 1 square inch of scalp
what is hair density
Long chain of amino acids linked by peptide bonds
what is polypeptide chain
small involuntary muscle in the dermis that attaches to the hair follicle; contraction of the muscle causes hair to stand, causing goose-bumps
what is arrector pili muscle
What type of hair always contains a medulla
What is beard hair
________ are bonds that cross-link polypeptide chains and are responsible for the extreme strength and elasticity of human hair
what are side bonds
In the context of the COHNS elements that make up human hair, _______ makes up 51 percent of a typical hair strand
what is carbon
fatty or oily secretion that lubricates the skin and preserves the softness of the hair
what is sebum
outermost layer of hair; formed from cells that resemble shingles on a roof; protects cortex
hair cuticle
in the context of the hair growth cycle, the ________ is the resting phase
what is telogen phase
the ________ is the fibrous protein layer of the hair
What is cortex
The hair's ability to stretch and return to its original length without breaking is referred to as ________
what is hair elasticity
process by which newly formed cells in the hair bulb mature, fill with keratin, move upward, lose their nucleus and die
what is keratinization
scientific study of hair and its diseases and care
what is trichology
What are the tiny grains of pigment in the cortex that give natural color to the hair?
What is melanin
the _______ is a cone-shaped elevation at the base of the hair bulb and contains blood vessels that supply nutrients that allow the hair to grow
what is dermal papilla
In the context of the hair growth cycle, the _______ is the growth phase
what is anagen phase
yellow to red pigment found in natural blonde to red shades of hair
what is pehomelanin
part of the hair that projects above the epidermis
what is the hair shaft
A ________ is a strong chemical side bond that joins the sulfur atoms of two neighboring cysteine amino acids within the polypeptide chains
What is disulfide bond
In the context of the types of body hair, _______ is long, pigmented hair on the scalp and body
what is terminal hair
The _______ is the innermost layer found in coarse hair and beard hair and is also known as the hair's pith or core
what is medulla
occurs when hair leaves the follicles at an angle; hair grows in a circular pattern on the crown of the head
what is a whorl
bonds created when disulfide bonds are broken by hydroxide chemical hair relaxers
what are lanthionine bonds