Chapter 11

Properties of the Hair & Scalp

• Identify and distinguish the different structures of the hair root.

• Point out and differentiate the differences among the three main layers of the hair shaft.

• Identify and explain the three types of side bonds in the cortex.

• Name and compare the differences among the three cycles of hair growth.

Learning Objectives

(continues)

• Give examples of the common types of hair loss and explain what can cause hair loss.

• Identify and explain at least three options for hair loss treatment.

• Learn to identify the most common hair and scalp disorders seen in the salon and school, and then name which ones a physician should treat.

• Compare and describe the different factors that should be considered during a hair and scalp analysis.

Learning Objectives (continued)

• Hairstylists play an important role in many people’s lives.

• All hair services must be based on a thorough understanding of the growth, structure, and composition of hair.

Introduction

Discover the Structure of Hair

• Trichology – the scientific study of hair, its diseases, and its care

• Hair root – the part of the hair located below the surface of the epidermis (outer layer of the skin)

• Hair shaft – portion of the hair that projects above the epidermis

Structures of the Hair Root

• Hair follicle– Distribution– Growth

• Hair bulb• Dermal papilla• Arrector pili muscle• Sebaceous glands

Structures of the Hair Shaft

• Hair cuticle

• Cortex

• Medulla

Learn About the Chemical Composition of Hair

• Hair is approximately 90 percent protein. • The protein is made up of long chains of amino

acids, which, in turn, are made up of elements. • The major elements that make up human hair are

carbon, oxygen, hydrogen, nitrogen, and sulfur and are often referred to as the COHNS elements.

• These five elements are also found in skin and nails.

COHNS Elements

• Carbon – 51 percent

• Oxygen – 21 percent

• Hydrogen – 6 percent

• Nitrogen – 17 percent

• Sulfur – 5 percent

Keratinization

• Keratinization – maturing process of living cells that originate within the hair follicle.

• As these newly formed cells mature, they fill up with a fibrous protein called keratin.

Amino Acids

• Linked like pop beads

• Peptide or end bonds

• Polypeptide chain

• Helix

Side Bonds of the Cortex

• Hydrogen bonds

• Salt bonds

• Disulfide bonds

• Lanthionine bonds

Bonds of the Hair

Hair Pigment

• Melanin – tiny grains of pigment– Eumelanin – provides dark brown/black color– Pheomelanin – provides yellow to red/ginger color

• Natural hair color – result of ratio of eumelanin to pheomelanin

• Gray hair – absence of melanin

Wave Patterns

• Straight hair

• Wavy hair

• Curly hair

• Extremely curly hair

The Truth About Hair Growth

• Types of hair

– Vellus hair: short, fine, downy, unpigmented hair on body

– Terminal hair: long, thick, pigmented hair found on scalp, legs, arms, and body

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Growth Cycles of Hair

• Anagen – growing phase

• Catagen – transition phase

• Telogen – resting phase

Myths and Facts About Hair Growth

• Myths

– Shaving, clipping, cutting makes hair grow faster.

– Scalp massage increases growth.

– Gray hair is coarser and more resistant.

– Natural curl determined by race.

– Round cross section is straight; oval cross section is wavy; flat cross section is curly.

Understand Hair Loss Causes and Treatment

• The growth cycle provides for the continuous growth, fall, and replacement of individual hair strands.

• Natural shedding: 35 to 40 hairs per day

Emotional Impact of Hair Loss

Perception of bald and balding men:

• Less attractive

• Less assertive

• Less successful

• Less personally likeable

• Older by five years

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• Men

– Negative social and emotional effects

– Preoccupation with baldness

– Effort made to conceal

• Women

– Devastation

– Anxiety

– Feelings of helplessness and unattractiveness

Emotional Impact of Hair Loss (continued)

Types of Abnormal Hair Loss

• Abnormal hair loss is called alopecia. • The three most common types of abnormal hair

loss:– Androgenic alopecia– Alopecia areata– Postpartum alopecia

Androgenic Alopecia

• Progressive shrinking or miniaturization of terminal hair

• Affects millions of men and women in the United States

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Alopecia Areata

• Sudden loss in round or irregular patches• Affects 5 million people in the United States• Immune system attacks hair follicles• Begins with small bald patches• Occurs in males and females

of all ages and races

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Postpartum Alopecia

• Temporary hair loss at conclusion of pregnancy

• Growth cycle returns to normal within one year after delivery of baby

Hair Loss Treatments

• Minoxidil – topical treatment

• Finasteride – oral treatment

Recognize Disorders of the Hair

• Canities– Congenital canities– Acquired canities

• Ringed hair

• Hypertrichosis

• Trichoptilosis

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• Monilethrix

• Fragilitas crinium

Recognize Disorders of the Hair (continued)

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Recognize Disorders of the Scalp

• Pityriasis

• Malassezia

• Pityriasis capitis simplex

• Pityriasis steatoides

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Fungal Infections

• Tinea

• Tinea capitis

• Tinea favosa

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Parasitic Infections

• Scabies – itch mite

• Pediculosis capitis – head lice

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Bacterial Infections

• Furuncle

• Carbuncle

• Folliculitis

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Perform a Thorough Hair and Scalp Analysis

• Hair Texture

– Coarse

– Medium

– Fine

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Hair Density

• Low: thin

• Medium: medium

• High: thick dense

• Average: 2,200 hairs per square inch

Porosity

• Low porosity

• Average porosity

• High porosity

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Elasticity

• Normal elasticity

• Low elasticity

• Testing for elasticity

Hair Growth Patterns

• Hair stream – hair flowing in same direction

• Whorl – hair forms in a circular pattern

• Cowlick – tuft of hair that stands straight up

Dry Hair and Scalp

• Hair appears dull, dry, lifeless.

• Avoid frequent shampooing, strong soaps, detergents, or products with a high alcohol content.

Oily Hair and Scalp

• Use normalizing shampoos.

• Eat a well-balanced diet.

• Exercise.

• Shampoo regularly and frequently.

• Practice good personal hygiene.

Summary and Review

• Trichology enables the professional cosmetologist to better understand both the physical and microscopic properties of the hair.

• You must be able to recognize those conditions of the hair and scalp needing treatment.

• Practicing proper disinfection procedures that are approved by your oversight regulatory agency will prevent the spread of disease.

Chapter Review Questions

1. Name and describe the five main structures of the hair root.

2. Name and describe the three layers of the hair.

3. Describe the process of keratinization.

4. What are polypeptide chains?

(continues)

5. List and describe the three types of side bonds. Indicate whether they are strong or weak and why.

6. Name and describe the two types of melanin responsible for natural hair color.

Chapter Review Questions (continued)

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7. Name and describe the two types of hair and their locations on the body.

8. What are the three phases of the hair growth cycle and what occurs during each?

9. What is the reason for normal daily hair loss?

10. What are the most common types of abnormal hair loss?

Chapter Review Questions (continued)

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11. What are the only two approved hair loss treatments?

12. Name the two main types of dandruff and state whether either can be treated in the salon.

13. Which scalp and hair disorders cannot be treated in the salon?

14. What four factors should be considered in hair analysis?

Chapter Review Questions (continued)