HAIR BIOLOGY DR. HEBA M. DIAB Associate Prof: Dermatology, Venereology & Andrology Ain-Shams University Hospitals
Guess who? Where will they be without the advances in hair industry and cosmetics!!!
Hair is the foundation for a multi million dollar industry focused on presenting, augmenting, and preserving scalp hair plus removing unwanted body hair. • Hair styles are used to make a statement, to identify the individual with a particular faction of society
It reflect general health , vitality of an individual. Aid in camouflage : survival ; mute tones blend with the animal's environment. One square centimeter of skin contains about 10 hair follicles and 15 sebaceous glands, 100 sweat glands
Hair follicle embryogenesis overview 1st primordial foll. forms 9 weeks [eyebrows. Upper,lower lip, chin] Most of Hair 4-5 th month gestation. [cephalo-caudal] Exchange of signals between: Epith. Cells Mesechymal cells crowding of basal Keratinocytes forming a bud PLACODE Follicular germ
Follicular neogenesis Follicular peg. • Elongation of f.peg cord. • Mesenchymal cells lining epid.cord F. sheath. • Conc. ones on tip Derm. Papilla. • Further elongation into the dermis development of hair follicle
HAIR CYCLE • ANAGEN: growing 2-3 y • CATAGEN: F. regression 2-3 w • TELOGEN: resting 2-3 m • EXOGEN: shedding
Dermal Papilla: • Growth of hair in ANAGEN.
HAIR cycle : • BIOLOGICAL CLOCK : • Winter coat. • Anagen only
Does h.cycle affect ANGIOGENESIS? • Studies on rats: injecting dye indicated a change in the density of the perifollicularand follicular blood vessels AnagenTelogen Dense population [----] [+++]
Does the dermis affect the hair follicle or is it the other way round???? • Certain angiogenic factors detected as VEG-F were secreted from papilla fibroblasts and outer root sheath keratinocytes. • = hair follicle seems to have the upper hand in controlling the dermis milieu.
Forms and Shapes of hair • Straight hair follicle • Curved hair follicle
To what length can our hair grow? • Genetically determind. • Growth rates by age & body regions:
Hair color –Biochemistry: • All diff colors and shades come from only 2 melanin pigment types: • Pheomelanin [light] Eumelanin [Dark]
Food for your Hair: • Salmon & Oysters: omega-3’s ,proteins dry scalp, dull. vitamin B-12 and iron, antioxidents. • Eggs & Poultry: contain biotinand B-12: for all matters of beauty including great hair, skin, and nails. • Dark green vegetables: Spinach, broccoli, eat for a luscious head of hair. vitamins A and C, sebum, [natural hair conditioner]. iron and calcium • Beans & Whole grains: protein to encourage hair growth: iron, zinc, and biotin:[ 3 cups every week ] • Nuts:Walnuts contain alpha-linoleic acid which is an omega-3 fatty acid, contain zinc. : hair shedding.
Quick hair tips: • 1) Consider a short hair style. Long hair is old hair. Old hair is weathered, damaged hair. To keep hair young, keep it short! • 2) When washing hair don't scrub. This flakes the cuticle. It is better to "milk" the hair from the forehead backwards in the same direction, shines more • 3) If you have dry hair try to avoid daily hair washing & Shampoo can be quite damaging to the hair fiber. consider using a very mild shampoo with a separate conditioner. • 4) Use a mild shampoo. Look at the shampoo ingredients. Avoid harsh detergents such as sodium lauryl sulfate. Sodium laureth sulfate is milder
5) Avoid shampoos with plant oils in them. They are very popular, but they can be quite harsh oils. They are also more likely to promote scalp dermatitis & can be utilized by bacteria as a food source. • 6) If you have dull, dry, problem hair don't even think about dying your hair or using relaxants or similar. Any chemical action on the hair like this breaks down the chemical bonds of the hair cuticle and cortex. Permanent damage quickly sets in and your dull, dry hair will rapidly get worse
10) Brittle hair can be a genetic problem ,but there are usually formulations specifically for hair typically including things like biotin, zinc, cysteine, silica, vitamin Bs, Folic acid that may help. • 11) Comb or brush in the direction of the cuticle (from hair root to tip). Find a metal comb or brush with metal teeth if possible. Plastic combs create static in dry hair making hair management more difficult. • 12) If possible avoid air pollution and excessive exposure to sunlight both of which can act on the chemical bonds of hair follicles and increase the rate of weathering. It is difficult to avoid but consider a baseball cap or similar.