the scientific study of the hair, it's diseases, and its care
The hair, skin and nails is collectively known as the
A mature stand of hair is divided into what 2 parts?
located below the surface of the scalp
the portion of the hair that projects above the skin
What are the 5 structures of the hair root?
Which part of the root contains the blood and nerve supply that provides the nutrients needed for hair growth?
*Thickened, club shape structure that forms the lower part of the hair root
*Lowest part of a hair strand
*Tube-like depression or pocket in the skin or scalp that contains the hair root
*Surrounds the dermal papilla
Which muscle when contracted cause goosebumps?
An oily substance secreted from the sebaceous glands that lubricate the hair and skin
What are the 3 main layers of the hair shaft?
What is the outermost layer of the hair?
*Provides a barrier that protects the inner structure of hair
*Creates shine and silkiness
*Looks like shingles on a roof
Protects hair from penetration & prevents damage to the hair fiber
What does a healthy cuticle layer protect?
In order to penetrate the cuticle layer, because a high pH swells the cuticle causing it to lift and expose the cortex
Why must haircolors,permanent waving solutions and chemical hair relaxers have an alkaline pH?
The middle layer
Which layer of the hair is the cortex?
What % of weight of the hair comes from the cortex?
In what layer of the hair do changes involving oxidation haircolor, wet setting thermal styling, permanent waving and chemicle hair relaxing take place?
The innermost layer of the hair that is composed of round cells
Hair is composed of ________ that grows from cells originating within the hair follicle.
The maturation of these cells is a process called
Living cells mature through Keratinization. As they mature, they fill up with keratin, then move upward, lose their nucleus and die.
Explain why hair is not a living thing.
What are the main elements that make up human hair and their percentages in normal hair?
*The unit of structure that builds protein
*Linked together end to end like pop beads
The spiral shape of a coiled protein
*The chemical bond that links amino acids
*Also called an end bond
*A long chain of amino acids linked by peptide bonds
*Cross linked like the rungs on ladder by 3 different kinds of salt bonds
Polypeptide chains are cross-linked together using 3 different types of cross links called
*A weak physical side bond that is easily broken by water or heat
*Weakest of all bonds
*Creates a TEMPORARY physical change in the hair
*Account for 1/3 of the hair's overall strength
*Weak , TEMP side bonds between adjacent polypeptide chains
*Greatly affected by changes in pH
*Cause the hair to sell and the cuticle to lift
*A strong chemical side bond that joins the sulfur atom of 2 neighboring cysteine amino acids to create cystine
*2nd strongest bond in hair, also called a sulfur bond
*NOT broken by heat or water
*Altered only by salon chemicals. Permanent waving, etc solutions break and rearrange these bonds
*The bonds created when disulfide bonds are broken by hydroxide chemical hair relaxers after the relaxer is rinsed from the hair.
*Broken PERMANENTLY and can never be reformed
The layer of the hair that all natural color is located in
tiny grains of pigment that give natural color to hair
What are the 2 types of melanin?
provides brown and black color to hair
provides color ranging from red and ginger to yellow/blond tones
Refers to the shape of the hair strand and is described as straight, wavy, curly or extremely curly
Natural wave pattern is the result of _______.
In extremely curly hair, cross sections are highly _____ and vary in shape and thickness along their length.
What are the 4 most important factors to consider in hair analysis?
Thickness/diameter of the individual hair strand
The ability to absorb moisture
The ability of the hair to stretch and return to it's original length without breaking
measures the number of hair strands on 1 square inch of the scalp
What are the 3 classifications of hair texture?
*Has largest diameter
*More difficult to process
*No special problems or concerns
Hair density can be classified as?
What is the average hair density per square inch?
How many hairs does the average head contain?
The condition of the cuticle layer
What is the degree of porosity directly related to?
______ hair has a raised cuticle that easily absorbs moisture
Less akaline solutions
Chemical services performed on overly porous hair require what type of solutions?
Hair with average porosity is considered ______.
Overly porous hair
What type of hair is damaged, dry, fragile and brittle?
How to check for porosity
Take a strand from 4 different areas (front, hairline, temple, crown and nape). Hold the strand with one hand while sliding thumb and forefinger of other hand from end to scalp
If it feels smooth...
and the cuticle is compact, dense and hard it is considered resistant.
If you can feel a slight roughness...
it is considered porous.
If the hair feels very rough or dry or breaks...
it is considered highly porous and may have been overly processed.
Wet hair with normal elasticity will stretch up to ____ of it's original length and return without breaking.
How much does dry hair stretch?
Hair follicles always from perpendicular (90 degree angle) to the scalp
Hair following in the same direction
Hair that forms in a circular pattern
A tuft of hair that stands straight up
Overactive sebaceous glands
What causes oily hair and scalp?
Inactive sebaceous glands
What cause dry hair and scalp?
What are the 2 types of hair found on the body?
*Short, fine and downy
*Almost never has a medulla
*Usually found on infants and young children
*In adults, it's found on most areas of body, not including scalp
*Courser than vellus
*It's pigmented with the exception of grey hair
*Usually has a medulla
Where is terminal hair found?
What are the 3 phases of a hair cycle?
*The growth phase of hair (when new hair is produced)
*Generally last from 3-5 years but can last up to 10 years
What percentage of hair is in the anagen phase at any given time?
*The brief transition period between the growth and resting phases
*Signals the end of the growth phase
*Last from 1 -2 weeks
*The resting phase
*Final phase and lasts until the fully grown hair is shed
*Last approx. 3-6 months
What is the average growth of healthy hair per month?
What percentage is in the catagen phase at any one time?
What percentage is in the telogen phase at any one tim
Abnormal hair loss
*Causes miniaturization of terminal hair, converting it to vellus
*The result of genetics, age and hormonal changes
Male Pattern Baldness
*In men, Androgentic Alopecia is known as______.
*It usually progresses to the familiar horseshoe shaped fringe of hair.
How many people does androgenic alopecia affect in the United States?
*The sudden falling out of hair in round patches or baldness in spots
*May occur on the scalp and elsewear on the body
A temporary hair loss experienced at the conclusion of a pregnancy
Minoxidil (Men & Women)
Finasteride (Men Only)
What are the only 2 products that have been proven to stimulate hair growth and are approved by the FDA?
*Most common surgical procedure for hair loss
*Consist of removing small sections of hair usually from the back and transplanting into the bald area
What non-medical options can a hairstylists offer to counter hair loss?
Technical term for grey hair
A variety of canites characterized by alternating bands of grey and pigmented hair through out the length of the hair strand.
*Also known as Hirsuties
*A condition of abnormal hair growth
*Characterized by the growth terminal hair in areas where only vellus hair grows
*ex, mustache, beard on women
Technical term for split ends
*Characterized by brittleness and the formation of nodular swellings along the hair shaft.
*Hair breaks easily, and the broken fibers spread out like a brush along the hair shaft
*Technical term for beaded hair
*The hair breaks easily between the beads or nodes.
*Technical term for brittle hair
*The hairs may split at any part of it's length.
What are the 2 types of canities?
Medical term for dandruff
Medical term for ringworm
*Ringworm of the scalp
*Fungal infection characterized by red papules or spots at the opening of the hair follicles
Caused by a parasite called a mite that burrows under the skin
An acute, localized bacterial infection of the hair follicle
An inflammation of the subcutaneous tissue caused by staphylococci
naturally occuring fungus that is present on all human skin, and is responsible for dandruff
Pityriasis Capitis Simplex
technical term for classic dandruff, characterized by scalp irritation, large flake and itchy scalp
a severe type of dandruff characterized by an accumulation of greasy or waxy scalp scales mixed with sebum
*Characterized by itching, scales and sometimes painful circular lesions