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CHAPTER 11 PROPERTIES OF THE HAIR AND SCALP 2012 Edition PowerPoint Presentation
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  2. Q. What are the two ADD: chief purposes of hair? • Protection • Adornment Add to the side bar: Hair is an appendage of the skin

  3. TRICOLOGY • scientific study of hair, its diseases, and care • comes from Greek words: Trichos=hair ology=the study of

  4. Integumentary System ~the outer covering that encloses the entire body • includes the hair, skin, nails, and glands ***is the largest and fastest growing organ body,r:2,s:15&tx=49&ty=84


  6. hair is divided into two parts: Hair root ~located below the surface of the epidermis (outer layer of the skin) Hair shaft ~projectsabovethe epidermis

  7. Structures of the Hair Root The main structures are: • Follicle • Bulb • Dermal papilla • Arrector pili muscle • Sebaceous glands

  8. Follicle ~ tube-like depression or pocket in the skin or scalp ~ contains the hair root ~ distributed all over the body ~ except *palms of the hands *soles of the feet ~ multiple hairs/one follicle

  9. The follicle “Tunnel” epidermis(outer layer of the skin) dermis (inner layer of the skin) Surrounds the dermal papilla Internet source:

  10. Hair bulb-the lowest area or part of the hair strand. • thickened, club-shaped part of the hair root • fits over and covers thedermal papilla Internet source:

  11. Dermal papilla ~ cone-shaped elevation ~ base of the hair follicle ~ fits into hair bulb. • contains theblood and nervesupply • providesnutrients • “mother of the hair”

  12. Arrector pili: • small, involuntary muscle ~ base of the hair follicle. • Strong emotions(fear) • or cold ~ contracts “goose bumps”

  13. Sebaceous glands ~ oil glands ~ connected to the hair follicles. ~ secretes oily substance ~ sebum ~ lubricates

  14. Sebaceous gland

  15. Structures of the Hair Shaft Three main layers • 1. Cuticle ~ outermost layer of hair ~ overlapping layer of transparent, scale-like cells ~ shingles on a roof

  16. ~provides a barrier/protects inner structure ~lies tightly against the cortex ~ creates shine, smooth silky feel **Show----Feel hair strand (both ways) • hair’s primary defense against damage Internet source: the gentle

  17. Individual cuticle scales are attached to the cortex ***The hair has only one cuticle layer Q. Why are we cautioned that there is only one cuticle layer?

  18. Swelling the hair: ~ raises the cuticle layer ~ opens the space between the scales ~allows liquids to penetrate

  19. Internet source: Damaged cuticle • Haircolor, permanent waving solutions, and chemical hair relaxers must have an alkaline (base) pH to penetrate the cuticle layer • Swells cuticle/lifts/exposes cortex • Q. Is haircolor spelled correctly?

  20. Cortex-is the middle layer of the hair ~ fibrous protein ~elongated cells ~melanin pigment Q. What does the word melanin mean?

  21. ~ elasticity of the hair ~ natural color ~ located in the cortex • all changes (physical or chemical)take place within the cortex • Activity: With a partner list on paper (be specific) • Q. Determine what services create a physical change to the hair and which ones create a chemical change to the hair. • 2 people from each table write two answers on flip chart paper

  22. Answer: Physical-wet setting (rollers, pin curls, finger waves), thermal styling (includes blow drying, curling iron, flat iron, hot rollers, press and curl) Chemical-permanent haircolor, hair lightening, permanent waving, chemical relaxing

  23. In book- page222 Internet source:

  24. Medulla-the inner most layer ~ composed of round cells *missing medulla ~ very fine hair ~ naturally blonde hair ~coarse hair contains a medulla

  25. Internet source:

  26. All beard hair contains a medulla • not involved in salon services Add to side bar: Barba-hair of the face Capilli-hair on the head Cilia-hair of the eyelashes Supercilia-hair of the eyebrows

  27. THE CHEMICAL COMPOSITION OF HAIR • composed of protein in the hair follicle ADD: keratin • This is where the hair shaft begins • living cells form • journey upward through the hair follicle

  28. process called keratinization. • As the cells mature ~ fill up with a fibrous protein ~keratin ~move upward

  29. ~ lose their nucleus ~ die ~ emerges from the scalp, ~ cells are keratinized ~ no longer living ~ nonliving fiber of keratinized protein

  30. ~ 90% protein ~protein made up of long chains of amino acids Main elements: (chemical composition) Carbon Oxygen Hydrogen Nitrogen Sulfur,r:10,s:16&tx=61&ty=70

  31. Referred to as the COHNS elements • Also found in skin and nails • Add: chemical composition Top of page shows the % of each element.

  32. Amino acids-long chains of protein • joined together like pop beads(candy necklace) The chemical bond that joins the amino acids to each other is called a peptide bond or end bond.

  33. A long chain of amino acids linked by peptide bonds is called a polypeptide. • spiral shape of coiled protein is called a helix. • Activity: • Do helix project

  34. THE SIDE BONDS OF THE CORTEX • made up of millions of polypeptide chains • Polypeptide chains are cross- linked by three different types of side bonds:

  35. Responsible for: • Extreme strength • Elasticity • Essential to: • Wet sets • Thermal styling • Permanent waving • Chemical hair relaxing

  36. Three types 0f Side Bonds: • Hydrogen bonds • Salt bonds • Disulfide bonds • Q. In the chart, what can be said about the three types of bonds?

  37. Hydrogen bond • weak physical side bond • Easily broken by waterorheat • Accounts for 1/3 of hair’s strength

  38. Wetting the hair: • Allows the hair to be stretched and wrapped around rollers/rods • Reforms when the hair dries,r:4,s:171

  39. Salt bond • weak physical side bond • Depend on pH • Easily broken by -strong alkaline or acidic solutions • Accounts for 1/3 of hair’s strength

  40. Disulfide bond ~strong chemical side bond • accounts for 1/3 overall strength • Not broken by heat or water • Broken by: ~ permanent waves ~ chemical relaxers ~alters the shape of the hair

  41. Thio permanent waves (base) ~ break the disulfide bonds ~ reformed by thio neutralizer (acid) • Hydroxide chemical hair relaxers ~ break disulfide bonds ~ bonds are broken permanently (becomes lanthionine bond) ~ can never be reformed

  42. Go over Figure 11-7 and 11-8 Read: Table 11-2 top of page Read: Did you know-next page

  43. Hair Pigment: ~ pigment located in the cortex Melanin ~ tiny grains of pigment ~ cortex

  44. The two main types: • Eumelanin • brownand black 2.Pheomelanin red /ginger yellow/blonde ~result: natural hair color- ratio of both

  45. Wave Pattern • Refers to the shape of the hair strand Described as: • straight • wavy • curly • extremelycurly

  46. result of genetics General rule: Asians ~extremely straight hair Caucasians ~straight to wavy hair African Americans ~extremely curly hair

  47. all wave patterns ~ in all races • vary from strand to strand ~ same person’s head • theories to explain the cause of natural curly hair

  48. One theory-the shape of the cross-section (round, oval, flat), determines the amount of curl, however, the shape of the cross-section does not always relate to the amount of curl. • Another theory-the result of one side of the hair strand growing faster than the other side, tension with in the strand causes the long side to curl around the short side. (not proven)