Podcast
Questions and Answers
What is the scientific study of hair and its diseases and care?
What is the scientific study of hair and its diseases and care?
Trichology.
What two Greek words does the word trichology come from?
What two Greek words does the word trichology come from?
Trichos (hair) & ology (the study of).
What are the two parts that human hair is divided into?
What are the two parts that human hair is divided into?
The hair root and the hair shaft.
What is the hair root?
What is the hair root?
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What is the hair shaft?
What is the hair shaft?
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What are the five main structures of the hair root?
What are the five main structures of the hair root?
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What is the hair follicle?
What is the hair follicle?
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What is the hair bulb?
What is the hair bulb?
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What is the dermal papilla?
What is the dermal papilla?
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Which structure of the hair root contains the blood and nerve supply that provides the nutrients needed for hair growth and is also known as the mother of the hair?
Which structure of the hair root contains the blood and nerve supply that provides the nutrients needed for hair growth and is also known as the mother of the hair?
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What is the arrector pili muscle?
What is the arrector pili muscle?
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How many of the 20 amino acids can your body naturally produce?
How many of the 20 amino acids can your body naturally produce?
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What are the three main layers of the hair shaft?
What are the three main layers of the hair shaft?
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What must an oxidation hair color, permanent waving solution, and chemical hair relaxer have to penetrate the cuticle layer?
What must an oxidation hair color, permanent waving solution, and chemical hair relaxer have to penetrate the cuticle layer?
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What is the hair shaft that emerges?
What is the hair shaft that emerges?
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What are the five major elements that make up human hair?
What are the five major elements that make up human hair?
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What are the five major elements that make up human hair referred to as?
What are the five major elements that make up human hair referred to as?
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What percent of the hair is made up of carbon?
What percent of the hair is made up of carbon?
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What percent of the hair is made up of oxygen?
What percent of the hair is made up of oxygen?
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What percent of the hair is made up of hydrogen?
What percent of the hair is made up of hydrogen?
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What percent of the hair is made up of nitrogen?
What percent of the hair is made up of nitrogen?
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What percent of the hair is made up of sulfur?
What percent of the hair is made up of sulfur?
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What are joined together end-to-end like pop beads?
What are joined together end-to-end like pop beads?
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What is the strong, chemical bond that joins amino acids?
What is the strong, chemical bond that joins amino acids?
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What is a long chain of amino acids linked by peptide bonds called?
What is a long chain of amino acids linked by peptide bonds called?
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What are long, coiled complex polypeptides made of amino acids?
What are long, coiled complex polypeptides made of amino acids?
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What is the spiral shape of a coil protein called?
What is the spiral shape of a coil protein called?
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What is a hydrogen bond?
What is a hydrogen bond?
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How are hydrogen bonds broken?
How are hydrogen bonds broken?
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When do hydrogen bonds reform?
When do hydrogen bonds reform?
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What is a salt bond?
What is a salt bond?
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How are salt bonds broken?
How are salt bonds broken?
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What is a disulfide bond?
What is a disulfide bond?
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How is the disulfide bond different from a hydrogen or salt bond?
How is the disulfide bond different from a hydrogen or salt bond?
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How are disulfide bonds broken?
How are disulfide bonds broken?
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What breaks and reforms disulfide bonds?
What breaks and reforms disulfide bonds?
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After hydroxide chemical hair relaxers break disulfide bonds what do they convert them to?
After hydroxide chemical hair relaxers break disulfide bonds what do they convert them to?
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What refers to the shape of the hair strand and describes a straight, wavy, curly, or extremely curly?
What refers to the shape of the hair strand and describes a straight, wavy, curly, or extremely curly?
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What is hair with a round cross-section?
What is hair with a round cross-section?
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What is hair with an oval to flattened cross-section?
What is hair with an oval to flattened cross-section?
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What is hair with a flattened to flatten oval cross-section?
What is hair with a flattened to flatten oval cross-section?
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What are the two types of hair found on the body?
What are the two types of hair found on the body?
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What is vellus hair?
What is vellus hair?
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What is terminal hair?
What is terminal hair?
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Who does scalp hair grow faster on?
Who does scalp hair grow faster on?
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What ages does scalp hair grow the most rapidly?
What ages does scalp hair grow the most rapidly?
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What age does hair growth slow down sharply after?
What age does hair growth slow down sharply after?
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How long does it take for the entire growth cycle to repeat itself?
How long does it take for the entire growth cycle to repeat itself?
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What do recent measurements indicate that the average rate of hair loss is?
What do recent measurements indicate that the average rate of hair loss is?
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What is abnormal hair loss called?
What is abnormal hair loss called?
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What are the three most common types of abnormal hair loss?
What are the three most common types of abnormal hair loss?
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What is androgenic alopecia?
What is androgenic alopecia?
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What is alopecia areata?
What is alopecia areata?
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How does alopecia areata begin?
How does alopecia areata begin?
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What is alopecia totalis?
What is alopecia totalis?
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What is alopecia universalis?
What is alopecia universalis?
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What is postpartum alopecia?
What is postpartum alopecia?
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What is canities?
What is canities?
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What is hypertrichosis?
What is hypertrichosis?
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What is trichoptilosis?
What is trichoptilosis?
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What is trichorrhexis nodosa?
What is trichorrhexis nodosa?
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What is monilethrix?
What is monilethrix?
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What is fragilitas crinium?
What is fragilitas crinium?
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What is pityriasis?
What is pityriasis?
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What is malassezia?
What is malassezia?
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What is pityriasis steatoides?
What is pityriasis steatoides?
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What is tinea?
What is tinea?
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What is tinea favosa?
What is tinea favosa?
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What are scabies?
What are scabies?
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What is pediculosis capitis?
What is pediculosis capitis?
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What is a furuncle?
What is a furuncle?
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What is a carbuncle?
What is a carbuncle?
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What is hair texture?
What is hair texture?
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What can hair texture be classified as?
What can hair texture be classified as?
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What is hair density?
What is hair density?
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What is the average number of hairs on blond hair?
What is the average number of hairs on blond hair?
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What is the average number of hairs on brown hair?
What is the average number of hairs on brown hair?
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What is the average number of hairs on black hair?
What is the average number of hairs on black hair?
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What is the average number of hairs on red hair?
What is the average number of hairs on red hair?
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Healthy hair with a compact cuticle layer that is naturally resistant to being penetrated by moisture is referred to as?
Healthy hair with a compact cuticle layer that is naturally resistant to being penetrated by moisture is referred to as?
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What is porous hair that has a raised cuticle layer that easily absorbs moisture called?
What is porous hair that has a raised cuticle layer that easily absorbs moisture called?
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What is a hair stream?
What is a hair stream?
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What is a whorl?
What is a whorl?
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What is a cowlick?
What is a cowlick?
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Dry hair and scalp should be treated with products that contain what?
Dry hair and scalp should be treated with products that contain what?
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Study Notes
Hair and Scalp Basics
- Trichology is the scientific study of hair, its diseases, and care.
- The term originates from the Greek words "trichos" (hair) and "ology" (the study of).
- Human hair consists of two main parts: the hair root (below the epidermis) and the hair shaft (above the epidermis).
Structure of Hair Root
- The hair root comprises five key structures: hair follicle, hair bulb, dermal papilla, arrector pili muscle, and sebaceous glands.
- The hair follicle is a tubelike pocket in the skin containing the hair root.
- The hair bulb is the thickened, club-shaped structure at the base of the hair strand.
- The dermal papilla nourishes hair growth with its blood and nerve supply, known as the "mother of the hair."
- The arrector pili muscle is a small, involuntary muscle at the hair follicle's base.
Hair Composition
- Hair is primarily composed of proteins, specifically keratinized protein fibers.
- There are 20 amino acids, 11 of which are produced naturally by the body.
- Human hair consists of three layers: the cuticle, cortex, and medulla.
- COHNS elements (carbon, oxygen, hydrogen, nitrogen, sulfur) make up human hair, with 51% carbon being the largest component.
Hair Bonds and Structure
- Amino acids link together by peptide bonds to form polypeptide chains.
- Hydrogen bonds provide weak cross-links between polypeptide chains and can be broken by water or heat.
- Salt bonds are weak physical bonds affected by strong alkaline or acidic solutions.
- Disulfide bonds are strong chemical side bonds that connect neighboring cysteine amino acids.
- Thio permanent waves and chemical relaxers can break disulfide bonds, converting them to lanthionine bonds.
Hair Growth and Loss
- Hair grows fastest in women and most rapidly between ages 15 and 30, slowing down sharply after 50.
- The complete hair growth cycle averages 4 to 5 years, with normal hair loss at 35 to 40 hairs per day.
- Abnormal hair loss, referred to as alopecia, includes types such as androgenic alopecia, alopecia areata, and postpartum alopecia.
Types of Hair
- Two main types of hair: vellus (short, fine, unpigmented) and terminal (long, coarse, pigmented).
- Hair texture variations include straight (round cross-section), wavy (oval), and curly (flattened).
- Hair density is defined by the number of hair strands per square inch, varying by hair color.
Hair Disorders
- Alopecia areata is an autoimmune disorder causing smooth bald patches.
- Conditions like hypertrichosis (abnormal hair growth) and canities (gray hair) describe specific hair issues.
- Dandruff (pityriasis) is linked to the overgrowth of malassezia fungus, while severe cases result in pityriasis steatoides.
Hair Characteristics
- Healthy hair has a hydrophobic nature, resisting moisture absorption, while porous hair with a raised cuticle is hydrophilic.
- Hair patterns include streams (flowing in the same direction), whorls (hair at an angle), and cowlicks (specific forehead patterns).
- Treatments for dry hair and scalp should include moisturizing and emollient products.
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Description
Test your knowledge on the properties of hair and scalp with these flashcards from Milady Chapter 11. Explore key terms such as trichology and the anatomy of hair. Perfect for students in cosmetology or anyone interested in hair care science.