Chapter 8 Hair Care. Properties off the Hair & Scalp. Chapter 8.
Chapter 8 Hair Care Properties off the Hair & Scalp
Chapter 8 • The hair is part of the body and , like every other part, must be cared for and nourished. Just as you replenish body fluids after extended exercising or illness, you must also replenish the needed nutrients for healthy hair. With all the styling tools and chemicals used on the hair today, it is constantly at risk of damage. It is essential that, as a hairdresser, you fully understand the importance of caring for the hair and scalp.
Structure of the Hair Shaft The three main layers of the hair shaft: cuticle cortex medulla
Hair Shaft • Cuticle • outermost layer of hair • consists of a single, overlapping layer of transparent, scale-like cells • like a roof shingles • hair’s primary defense against damage • each individual cuticle is attached to the cortex • imbrications • allows liquids to penetrate
Hair Shaft • Cortex • Middle layer of hair • Fibrous protein core formed by elongated cells containing melanin pigment • 90% of hair weight • Hair elasticity • Changes resulting from chemical services occur in the cortex
Hair Shaft • Medulla • Innermost layer • Referred to as the pith of the hair • Composed of round cells • Very fine & naturally blonde hair may not even have a medulla • Thick coarse hair & beard hair always contain a medulla
Chemical Composition of Hair • Hair is composed of protein that grows from cells originating within the hair follicle • Keratinization • Process during which newly formed cells in the hair mature • They fill up w/ keratin, move upward, lose their molecules, & die • The hair shaft is a nonliving fiber composed of keratinized protein
Chemical Composition of Hair • 91% protein • Cohns elements • Carbon – 51% • Oxygen – 21% • Hydrogen – 6% • Nitrogen – 17% • Sulfur – 5% • Amino acids • Units of structure in protein
Chemical Composition of Hair • Side bonds of cortex • Middle layer of hair is made up of millions of polypeptide chains • Cross-linked like a ladder by three different types of bonds • Hydrogen bonds • Physical side bond that is easily broken by water or heat • They are weak individually, but because there are so many, they account for about 1/3 of the hair’s strength
Chemical Composition of Hair • Salt bonds • Physical side bond that is broken by changes in pH. • Easily broken by strong alkaline or acidic solutions • Account for about 1/3 of the hair’s overall strength • Disulfide bonds • Chemical side bond that differs greatly from the physical side bonds
Chemical Composition of Hair • Disulfide bonds • Chemical side bond that differs greatly from the physical side bond • Join sulfur atoms of 2 neighboring cysteine amino acids to create cystine • Far fewer than the physical bond, but are stronger • Account for about 1/3 of the hair’s overall strength
Hair Pigment • All natural hair color is the result of pigment located within the cortex • Melanin • Tiny grains of pigment in the cortex that give natural color to hair • Eumelanin • Provides brown & black color • Pheomelanin • Provides natural colors from red & ginger to yellow-blonde tones
Hair Pigment • Natural hair color • Is the result of the ratio of eumelanin to pheomelanin, along with the total number & size of pigment granules • Gray hair • Caused by the absence of melanin. It grows in exactly the same way as pigmented hair but without the melanin pigment
Haircolor vs. Hair Color • Hair Color ( two words ) refers to the color of hair created by nature. • Haircolor ( one word ) is the term used in the beauty industry to refer to artificial haircoloring products.
Wave Pattern & Tendencies • Described as straight • Described as wavy • Described as curly • Described as extremely curly
Wave Pattern & Tendencies • Straight hair usually round • Wavy hair usually oval • Curly/extremely curly almost flat
Wave Pattern & Tendencies • Asians • Extremely straight hair • Caucasians • Straight to wavy • African-Americans • Extremely curly
Summary • Living cells form in the follicle and mature through keratinization • Three layers of the hair is cuticle, cortex and medulla • Hair has different wave patterns Next lesson – hair analysis