Hair Structure
What is the outermost layer of the hair shaft?
Cuticle
What is the process called when newly formed hair cells fill with keratin, move upward, lose their nucleus, and die?
Keratinization
What hair property describes the thickness or diameter of an individual strand?
Texture
What wave pattern has a round cross-section?
Straight
What are the three main types of body hair?
Lanugo, vellus, and terminal
Which layer of the hair provides strength, elasticity, and color?
Cortex
What is a long chain of amino acids linked by peptide bonds called?
Polypeptide
What hair property measures the number of individual strands per square inch of scalp?
Density
Hair flowing in the same direction because follicles slope in the same direction is called what?
Hair stream
Which phase of the hair growth cycle is the growth phase?
Anagen
Which structure is located at the base of the hair follicle and contains the living cells that form the hair strand?
Hair bulb
What are the three types of side bonds found in the cortex?
Hydrogen, salt, and disulfide bonds
What hair property describes the hair's ability to absorb moisture?
Porosity
What is created when two hair streams flow in opposite directions?
Natural part
Which phase is the brief transition period between the growth and resting phases?
Catagen
What involuntary muscle causes the hair to stand up and creates goose bumps?
Arrector pili muscle
Which side bond is easily broken by water or heat and reforms when the hair dries or cools?
Hydrogen bond
A client's hair feels very rough, dry, and breaks easily and it turned blue when ash toner was used. What does this indicate?
High porosity; the hair may be overprocessed.
Hair leaves the follicles at an angle and grows in a circular pattern. What growth pattern is this?
Whorl
Which phase is the resting phase and can involve normal shedding?
Telogen
What three structures make up the living portion of the hair?
Hair follicle, hair bulb, dermal papilla
What type of bond is formed when hydroxide relaxers permanently alter disulfide bonds?
Lanthionine bonds- they cannot be re-formed back into disulfide bonds.
You stretch a strand of wet hair and it breaks easily or does not return to its original length. What property is low?
Elasticity
Hair grows straight up or at a different angle than the surrounding hair, often near the crown. What is this called?
Cowlick
A client says her hair always seems to stop growing around the same length. Which phase of the growth cycle helps explain why some people's hair cannot grow beyond a certain length?
Anagen- the length of the anagen phase determines how long the hair can grow