Hair Structure!

Disulfide

-chemical bond; different from physical side bonds; fewer in number but stronger account for 1/3 not broken by heat or water chemicals like permanent waves and chemical hair relaxers change hair's strength change hairs disulfide bonds reformed by thio neutralizers disulfide bonds broken by chemical relaxers are broken permanently

epidermis

1st layer of the skin

Amino Acids

Are units of structure that build protein Linked together in long chains, like pop beads Peptide bond- chemical bond linking 2 amino acids together Also known as END bonds Long chains of amino acids linked by peptide bonds make up the polypeptide chain

Chemical Composition of Hair(COHNS)

Carbon 51% Oxygen 21% Hydrogen 6% Nitrogen 17% Sulfur 5%

cortex

Fibrous protein core formed by elongated cells containing melanin Makes up the hair's weight (90%) The elasticity of hair comes from cortex The changes involved in oxidative haircolor, wet setting, thermal styling, permanent waving and chemical hair relaxing take place in cortex

Keratinization

Hair composed of 90 % keratin protein Process happens by: Living cells within follicle begin to move up the hair follicle They mature in a process called keratinization Cells fill with keratin & move upward They lose their nucleus and die Then emerge from follicle & scalp as a nonliving fiber

Hair is made up of 3 side bonds

Hydrogen, Salt, Disulfide

bulb

Lowest part of the hair strand Thick, club-shaped structure- forms the lower part of the hair root

medulla

Medulla is the innermost layer of the hair Composed of round cells Fine and blond hair may not have a medulla All male beards contain a medulla Salon services do not involve the medulla

sebaceous (oil) glands

Oil glands in the skin that are connected to the follicle Produces sebum a fatty, oily substance that lubricates the skin

Salt

Relatively weak but numerous and so account 1/3 strength Strong alkaline or acidic solutions will break bonds Reformed when the pH has been reformed

dermal papilla

Small, cone-shaped elevation Located at base of the hair follicle and fits into the hair bulb

arrector pili muscle

The arrector pili muscles are small muscles attached to hair follicles in mammals. Contraction of these muscles causes the hairs to stand on end, known colloquially as goose bumps. ... Pressure exerted by the muscle may cause sebum to be forced along the hair follicle towards the surface, protecting the hair.

hair shaft

The hair shaft is the part of the hair that sticks out of the skin. The hair shaft is connected to the follicle.

Keratin

This protein is made up of long chains of amino acids Amino Acids are made of elements called COHNS

follicle

Tube-like depression that encases the hair root

ph

anything higher or lower than the ph of 4.4-5.5 is unhealthy hair, skin, nail

anagen phase

growing phase Average growth = 2 inches per month 90% of hair is growing at one time Grows for period of 2-6 yrs Duration is affected by age, gender, nutrition, health and your genes Grows faster on: Women than men Between ages 15-30 and slowest after 50!

neutralizer

might rebuild some of the disulfide bonds

cuticle

outer covering of hair

telogen

resting hair Follicle begins a 3-6 month resting phase About 10% of hair is in this phase at any one time REMEMBER the order: A C T

blowdry

salt/hydrogen

trichology

the study of hair

dermis

the thick layer of living tissue below the epidermis that forms the true skin, containing blood capillaries, nerve endings, sweat glands, hair follicles, and other structures.

catagen phase

transition phase Ends the growth phase Lasts only one to two weeks Follicle canal shrinks and detaches from the dermal papilla Hair bulb disappears and the shrunken root end forms rounded club Less than 1% in this phase at a time

Hydrogen

weak physical side bond easily broken by water or heat; however, numerous and so account for 1/3 strength 6% can be found in normal hair Bonds can be reformed when the hair dries

fact

your body can make up 11 to 20 of the amino acids