MILADY’S PROFESSIONAL BARBERING COURSE MANAGEMENT GUIDE LESSON PLAN 11.0 Chapter 11: Properties and Disorders of the Hair and Scalp TOPICS 1. Introduction 2. The Structure of Hair A. Description B. Hair Root and Hair Shaft C. Chemical Composition of Hair D. Hair Growth 3. Hair Analysis 4. Hair Loss 5. Disorders of the Scalp A. Common Disorders B. Staphylococci Infections 6. Disorders of the Hair A. Gray Hair B. Other Non-contagious Conditions NOTES TO THE INSTRUCTOR It is vitally important that students understand the structure of hair because many of the judgments and decisions they will have to make about client services are dependent upon this information. As student barbers, they need to be able to analyze the hair and then suggest appropriate treatments and services; this cannot be achieved without a thorough understanding of the variables (texture, density, growth patterns, etc.) that are applicable from one individual to another. Students should be reminded that their professional responsibilities should include the goal to maintain their clients’ hair in a healthy condition through proper care and treatment. STUDENT PREPARATION: Read Chapter 11: Properties and Disorders of the Hair and Scalp STUDENT MATERIALS • Milady’s Standard Professional Barbering textbook • Milady’s Professional Barbering Student Workbook • Milady’s Professional Barbering Student CD-ROM • Writing materials • Materials and supplies for 3-D model project LEARNING OBJECTIVES Upon completion of this lesson, students should be able to: 1. Name and describe the structures of the hair root. 2. List and describe the layers of the hair shaft. 3. Describe the structure of hair protein. 4. Describe the growth cycle of hair. 5. List the characteristics of hair important in hair analysis. 6. Identify different types of hair loss and treatments. 7. Identify common scalp disorders. 8. Identify common hair disorders. 216 © 2011 Milady, a part of Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 997147_11_ch11_p216-240.indd7147_11_ch11_p216-240.indd 216216 55/31/10/31/10 110:45:550:45:55 AAMM ALLOTTED TIME: Four to six hours, depending on depth of study and range of activities. TEACHING AIDS • Milady’s Standard Professional Barbering textbook • Milady’s Professional Barbering Instructor Slides • Whiteboard or chalkboard; dry-erase markers or chalk • CD/DVD player or overhead projector • Materials and supplies for 3-D model project EDUCATOR REFERENCES • Milady’s Standard Professional Barbering textbook • Milady’s Professional Barbering Course Management Guide LESSON OUTLINE 1. Introduction A. Technical understanding of hair structure important to providing knowledgeable and professional service to clients. B. Professional responsibility: proper care and treatment to maintain hair in a healthy condition C. Trichology: the scientifi c study of hair, its disorders, and its care D. Hair protects the head from heat, cold, and injury and is used as adornment. 2. The Structure of Hair Activity 1: Distribute copies of Supplement 11.0 to students. Have students fi ll in the blanks as the topic is discussed. Refer to Supplement 11.1 for the answer key. A. Description 1. An appendage of the skin; a slender, thread-like outgrowth of the skin and scalp 2. Composed chiefl y of the protein keratin B. Hair Root and Hair Shaft 1. Hair root: portion of the hair beneath the skin surface, enclosed within the follicle 2. Hair shaft: portion of the hair extending above or beyond the skin surface 3. Structures of the hair root a. Main structures: follicle, bulb, dermal papilla, arrector pili muscle, and sebaceous glands. (Refer to textbook Figure 11-1.) b. Follicle: tube-like depression in the skin or scalp that encases the hair root 1. Extends down from the epidermis on an angle into the dermis; surrounds the dermal papilla 2. Bottom contains a fi nger-like projection called the papilla, from which new hair develops 3. Variance in follicle depth depending on the thickness and location of the skin 4. A follicle for every hair; more than one hair may grow from a single follicle. 5. Mouth of hair follicle: breeding places for germs and accumulation of sebum and dirt c. Hair bulb: thickened, club-shaped structure that forms the lower part of the hair root 1. Lower part of the hair bulb is hollow 2. Fits over and covers the dermal papilla; see textbook Figure 11-2. d. Dermal papilla: small, cone-shaped elevation at the base of the hair follicle 1. Fits into the hair bulb 2. Contains capillaries responsible for supplying oxygen/nutrients to the follicle epidermal tissue 217 © 2011 Milady, a part of Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 997147_11_ch11_p216-240.indd7147_11_ch11_p216-240.indd 217217 55/31/10/31/10 110:45:550:45:55 AAMM 3. Epidermal tissue surrounds papilla and forms the hair bulb. 4. Blood and nerve supply vital to growth and regeneration of the hair. 5. Nourishment reaches the hair bulb through the papilla. 6. Healthy papilla results in new hair growth. e. Sebaceous glands: small, sac-like structures with ducts attached to each hair follicle 1. Secrete sebum that gives hair luster and pliability 2. Factors associated with sebum production: (a) diet: health of the hair declines in the absence of necessary food elements; (b) emotional stress: linked with the health of the hair through the nervous system; (c) endocrine glands: hormonal in nature; infl uence the hair and other aspects of health; (d) drugs: hormones and certain medications may affect the hair adversely. f. Arrector pili: minute, involuntary muscle fi ber in skin attached to the hair follicle 1. Fear or cold causes contraction and makes hair stand up straight; “goose bumps.” 2. Eyelash and eyebrow hairs lack arrector pili muscles. 4. Structure of the hair shaft a. Layers of the hair shaft: cuticle, cortex, and medulla; see textbook Figure 11-3. b. Cuticle: outermost layer of hair, consisting of a single overlapping layer of transparent cells; see textbook Figure 11-4. 1. Scale-like cells point away from the scalp toward the hair ends. 2. Hair’s primary defense against damage is a healthy, compact cuticle layer. 3. Certain chemical solutions soften and raise scales to allow absorption by the cortex. c. Cortex: middle layer of the hair 1. Protein core that contains melanin pigment 2. About 90 percent of total hair weight comes from the cortex. 3. Protein structure provides strength, elasticity, and natural color to the hair. 4. Changes in hair during chemical services occur within the cortex. d. Medulla: innermost layer of the hair; composed of round cells 1. Male beard hair contains a medulla. 2. Medulla may be absent in very fi ne or naturally blonde hair found on the head. C. Chemical Composition of Hair 1. Introduction a. Hair is composed of protein that grows from cells originating within the hair follicle. b. Keratinization: maturation of cells as they fi ll with keratin, lose their nuclei, and die c. Hair shaft: a nonliving fi ber composed of keratinized protein (approximately 91 percent) 2. Protein: essential organic compounds necessary for life a. Made of long chains of amino acids b. Five elements make up amino acids in hair; these are the COHNS elements. c. Human hair: 51 percent carbon, 21 percent oxygen, 6 percent hydrogen, 17 percent nitrogen, and 5 percent sulfur d. Chemical composition varies with color. 1. Light hair: less carbon and hydrogen; more oxygen and sulfur. 2. Dark hair: more carbon; less oxygen and sulfur. 3. Nature of hair protein a. Peptide or end bonds: chemical bonds that join amino acids end-to-end in a defi nite order 1. Peptide bonds: strongest chemical bonds in the cortex 2. Join each amino acid to form a polypeptide chain 3. Most strength and elasticity of the hair is attributed to peptide bonds. 4. There is no way to reform broken peptide bonds. 218 © 2011 Milady, a part of Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 997147_11_ch11_p216-240.indd7147_11_ch11_p216-240.indd 218218 55/31/10/31/10 110:45:550:45:55 AAMM 5. Chemical processes and rough treatment of hair can break peptide bonds. 6. Polypeptide or polypeptide chain: long chain of amino acids joined by peptide bonds 7. Polypeptide chains intertwine to create a coil of protein called a helix; see textbook Figures 11-5 and 11-6. b. Side bonds or cross bonds of the hair cortex 1. Hair cortex contains millions of polypeptide chains cross-linked by side or cross bonds to form a ladder-like structure. 2. Side bonds: hydrogen, salt, and disulfi de bonds; account for hair strength and elasticity. See textbook Figure 11-7. c. Hydrogen bond: physical cross bond; easily broken by water or heat 1. Individual hydrogen bonds are weak but numerous. 2. Account for about one-third of hair’s overall strength 3. Add body to the hair 4. Help to keep parallel chains of polypeptides together 5. Also known as H-bonds 6. Water, dilute alkali, neutral, and acid solutions will break hydrogen bonds. 7. Drying and dilute acids will reform hydrogen bonds (see Table 11-2). d.