1. 1 Shampoos Shampoos Conditioners Conditioners “2 in 1” shampoos “2 in 1” shampoos Hair sprays Hair sprays Hair Care Products

2. 2 Hair Care Products (con.) Hair gels Hair gels Perming solutions Perming solutions Hair dyes Hair dyes etc. etc. General remarks about product development General remarks about product development

3. a tiny cup-shaped pit burried deep in the fat of the scalp follicle is the point from which the hair grows well supplied with minute blood vessels temperature is normal body temperature 3 Hair Structure Hair follicle

4. temperature is not affected by cold or hot water the rate of growth depends on the amount of natural light : growing a little faster in winter when the days are short 4 Hair Structure (con.)

5. Hair follicle Hair bulb Hair shaft Hair bulb - lines in side the hair follicle - is a structure of actively growing cells - produce a long fine cylinder of hair - new cells are continuously produced in the lower part of the bulb 5

6. 6 (a) Longitudinal section of a hair within its follicle. (b) Enlarged longitudinal section of a hair.

7. 7 (c) Enlarged longitudinal view of the expanded hair bulb of (c) Enlarged longitudinal view of the expanded hair bulb of the follicle which encloses the matrix, actively dividing epithelial the follicle which encloses the matrix, actively dividing epithelial cells that produce the hair. cells that produce the hair.

8. 8 (d) Cross section of a hair and hair follicle.

9. 9 (e) Photomicrograph of scalp tissue showing numerous hair follicles (24 X ). hair follicles (24 X ).

10. can be seen above the scalp consist mainly of dead cell Keratin + binding material + small amount of water terminal hairs are lubricated by natural oil (sebum) produced by sebaceous glands high level of hormones (androgens) high level of sebum 10 The Hair Shaft

11. scales growing over the youngest part (closet to the scalp) are smooth and unbroken further along the hair have been damaged by cosmetic treatments and by mistreatment : (over- energetic brushing) 11 Nature of cuticle

12. 12 Nature of cuticle (con.) little by little, they may break away : little by little, they may break away : “weathering” healthy cuticle is more than just a protective layer healthy cuticle is more than just a protective layer intact cuticle cells are smooth, glossy, and reflect light from their surface (black hair reflects less light than blond hair) intact cuticle cells are smooth, glossy, and reflect light from their surface (black hair reflects less light than blond hair)

13. 13 The cuticle scale on a normal hair (electronmicrograph)

14. Another normal hair - but this came from one of our nearest relatives an orangutan! 14 A perfect hair seen under the electron microscope

15. keratin chains link by : disulphide bond and hydrogen bonds disulphide bonds can be changed by chemical methods : perming and relaxing permanent 15 Hair shape

16. hydrogen bonds can be easily broken apart whenever the hair is wetted and form again as it dries when they break the shape of hair changes wet hair is wound on the roller, the dried hair keep the roller shape temporary 16 Hair shape (con.)

17. individual hair form inside a hair bulb deep in hair follicle is tiny but powerful factory each hair grows during many years shampooed, conditioned, cut, blown dry, exposal to the sun and wind, colored, bleached, permed none of these affected the hair growth 17 Hair growth cycle

18. the hair spontaneously falls out the follicle rests for a little while and starts to produce a new hair 18 Hair growth cycle (con.)

19. anagen : the growing phase ( ~ 1000 days) catagen : the intermediate phase ( ~ 10 days) telogen : the shedding phase ( ~ 100 days) 19 Stage of the hair cycle

20. last between 3-7 years without interruption roughly 1 cm/month > 1 meter faster rate in winter than summer melanin is made in hair bulb throughout this phase 20 Anagen (the growing phase)

21. less pigment is made in older people, hair cycle becomes shorter follicles gradually give up producing long, strong hair : hairs become thinner and shorter thinning of the hair degree of baldness 21 Anagen (con.)

22. short resting phase : 2-4 weeks no pigment is made follicles stop producing hair the base of follicle moves upwards towards the surface of the skin 22 Catagen (the intermediate phase)

23. last for 3-4 months new hair begin to grow from the hair follicle as it grow s upwards the old hair will be shed naturally or easily be pulled out 23 Telogen (the shedding phase)

24. at anytime around one in ten of the follicles at individual’s head is in the shedding phase shedding is part of normal process of the replacement of old hair with new hair new hair emerges from the same opening as the old one 24 Telogen (con.)

25. 25 The hair follicle cycle

26. 26

27. 27 Pigmentation Melanin : - produced by melanocytes at growing phase (anagen) phase (anagen) - spread out throughout the cortex, the more near outer edge lie along the amino acid - spread out throughout the cortex, the more near outer edge lie along the amino acid chains chains - does not protect the harmful effect from - does not protect the harmful effect from sunlight sunlight - is found in 2 forms - is found in 2 forms Hair Color

28. Eumelanin : dark pigmented which predominates in black and brunette hair/oval shape Phaeomelain : lighter pigment, found in red and blond hair/smaller, partly oval and partly rod- shape 28 Pigmentation (con.)

29. 29

30. Strength Elasticity Static electricity Moisture content Porosity Texture 30 Physical properties of hair

31. a single hair can support a load of about 100 gm keratin protein of the cortex responsible for the hair strength keratin is a protein chains contain high concentration of an amino acid called “cystine” matrix contains high level of cystine 31 Hair strength

32. each cystine unit contains 2 cysteine amino acids in different chain the chains are linked by two sulphur atoms, forming a very strong chemical bond “disulphide linkage” many disulphide bonds form down the length of the keratin chains 32 Hair strength (con.)

33. 33 Chemical bonds within the hair maintain its shape

34. one of the most important properties can resist forces that could change its shape, volume and length lest spring back to its original form without damage wet hair can increase the length up to 30% and return to original length when it is dried 34 Elasticity

35. elasticity of hair depends on the long keratin fibers in the cortex chemical treatment can alter the cortex and change the hair elasticity 35 Elasticity (con.)

36. poor elasticity : - stretch only to a limited extent - will break easily - cannot be permed satisfactorily natural sunlight and artificial UV light damage chemicals of hair and its elasticity 36 Elasticity (con.)

37. Static electricity rubbing drug hair / brushing / combing builds up static electric charge the charges tend to push each other apart charged hair never lie smooth against each other “ fly away ” hair stands out from the head 37

38. 38

39. Moisture content : Heat and humidity more moisture less static electricity collapse Heat and dryness less moisture more static electricity more volume 39

40. - wet hair swell cortex / lift cuticle scales - hair surface temporaly loses its smoothness - wet hair more friction matting and tangles (over vigorous shampoo) 40 Moisture content (con.)

41. cuticle covering cortex is intact : almost water proof (very little water can go in and out) shampoos do not damage the cuticle treating the hair (permed or tinted) 41 Porosity Normal hair

42. temperature / applying an alkaline lotion separate the scale allowing chemicals to go inside after processing scales close up 42 Porosity (con.)

43. the larger the hair diameter the coarser it will feel different people’s hair naturally feel different soft / hard / silky / wiry effected by degree of weathering of hair 43 Texture

44. Texture is affected by what has been put on it : - spray : makes different feeling - conditioner : feel soft and smooth - conditioner with silicone : protect the hair cuticle - damage to cuticle : alter the hair texture 44 Texture (con.)

45. 45 Chemistry of Hair Keratinization process in the follicle keratin + water soluble substances : pentose, phenols, uric acid, glycogen, glutamic acid, valine, leucine

46. 46 Chemistry of Hair (con.) Keratin is composed of amino acid Keratin is composed of amino acid 18 out of 25 normal amino acids 18 out of 25 normal amino acids are found in keratin are found in keratin

47. 47 Organization of hair protein sets up by bonding in 3 ways : Chemistry of Hair (con.) between parallel peptide chains Formation of H-bonds I Formation of H-bonds

48. 48 between acidie and basic side chain Chemistry of Hair (con.) II Formaton of salt linkage

49. 49 Chemistry of Hair (con.) amino acid contains two amino and two carlygl groups link together by a disulphide bond III Formates of disulphide linkages

50. 50 Structure for - keratin Structure for  - keratin