Hair & Scalp Theory
What determines the natural shape or curl pattern of hair?
The shape of the follicle and the angle at which it enters the scalp
What is the underlying pigment (contributing pigment) exposed when lifting level 5 hair?
Red-Orange
What type of relaxer is recommended for sensitive scalps?
No-lye relaxer
What is the technical term for nail disease?
Onychosis
Which elevation creates maximum weight?
0°
Which layer of the hair shaft provides strength and elasticity?
Cortex
What is the process of diffusing natural hair pigment called?
Lightening or decolorizing
What is the main reducing agent in most alkaline perms?
Ammonium thioglycolate
What is the technical term for bitten nails?
Onychopagy
Which elevation creates uniform lengths?
90°
How does the hair’s porosity affect color absorption?
Highly porous hair absorbs color more quickly and may process unevenly
How does porosity impact toning results?
Overly porous hair may absorb too much tone or cause ashy results due to over-deposition
Explain how pH affects the swelling and penetration of hair during a chemical service.
Higher pH opens the cuticle and increases penetration; lower pH closes the cuticle
What layer of skin contains melanocytes?
Stratum basale (basal layer) or the stratum gemantivium
Raising the hair from the head while cutting is known as what?
Elevation
Which part of the hair structure contains living cells?
Hair Bulb
When performing a corrective color, why must you often fill the hair first?
Filling replaces missing underlying pigments to ensure even, lasting color
What is the primary difference between exothermic and endothermic perms?
Exothermic perms generate their own heat; endothermic perms require an external heat source
How does the nail matrix affect nail growth?
Damage to the matrix can permanently affect nail shape or growth rate
The gradual blending or disappearance of a line is known as what?
Tapering
Name three factors that affect the porosity of hair.
Chemical treatments, heat, environmental exposure
Describe the chemical reaction that occurs between aniline derivative tints and hydrogen peroxide.
Oxidation occurs—small colorless dye precursors penetrate the cortex and combine with oxygen to form large, permanent color molecules
What is the main difference between thio relaxers and hydroxide relaxers?
Thio can be neutralized; hydroxide permanently breaks disulfide bonds
Which layer of the skin contains blood vessels, nerves, and glands?
Dermis
Which elevation makes lengths longer from top to bottom?
180°