Chapter 11
Properties of the
Hair & Scalp
Learning Objectives
• 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.
(continues)
Learning Objectives (continued)
• 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.
Introduction
• 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.
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
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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
– Terminal hair: long, thick,
pigmented hair found on scalp,
legs, arms, and body
Pfizer Inc.
– Vellus hair: short, fine, downy,
unpigmented hair on body
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
(continues)
Emotional Impact of Hair Loss (continued)
• Men
– Negative social and emotional effects
– Preoccupation with baldness
– Effort made to conceal
• Women
– Devastation
– Anxiety
– Feelings of helplessness and unattractiveness
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
Pfizer Inc.
• Affects millions of men and women in the
United States
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•
•
•
•
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
Courtesy of Robert A. Silverman, M.D., Clinical
Associate Professor, Department of Pediatrics,
Georgetown University.
Alopecia Areata
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
– Congenital canities
– Acquired canities
• Ringed hair
• Hypertrichosis
• Trichoptilosis
Courtesy of P&G Beauty from the World of Hair by John Gray.
• Canities
(continues)
Recognize Disorders of the Hair (continued)
• Monilethrix
• Fragilitas crinium
Courtesy of P&G Beauty from the World of Hair by John Gray.
• Trichorrhexis nodosa
Recognize Disorders of the Scalp
• Malassezia
• Pityriasis capitis simplex
• Pityriasis steatoides
Photography: Courtesy of P&G Beauty
• Pityriasis
• Tinea favosa
Courtesy of Robert A. Silverman, M.D.,
Clinical Associate Professor, Department
of Pediatrics, Georgetown University.
Fungal Infections
• Tinea
• Tinea capitis
Courtesy of Hogil Pharmaceutical Corporation.
Courtesy of The National Pediculosis
Association,® Inc.
Parasitic Infections
• Scabies – itch mite
• Pediculosis capitis – head lice
Bacterial Infections
• Furuncle
• Folliculitis
© Inxti/Shutterstock.com
• Carbuncle
The Gillette Research Institute.
The Gillette Research Institute.
The Gillette Research Institute.
Perform a Thorough Hair and Scalp Analysis
• Hair Texture
– Coarse
– Medium
– Fine
Hair Density
• Low: thin
• Medium: medium
• High: thick dense
• Average: 2,200 hairs per square inch
The Gillette Research Institute.
The Gillette Research Institute.
The Gillette Research Institute.
Porosity
• Low porosity
• Average porosity
• High porosity
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)
Chapter Review Questions (continued)
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.
(continues)
Chapter Review Questions (continued)
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?
(continues)
Chapter Review Questions (continued)
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?