Milady Chapter 11 Hair and Scalp Properties

Questions and Answers

What is the scientific study of hair and its diseases and care?

Trichology.

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?

The hair root and the hair shaft.

What is the hair root?

The part of the hair located below the surface of the epidermis. Signup and view all the answers

What is the hair shaft?

The portion of the hair that projects above the epidermis. Signup and view all the answers

What are the five main structures of the hair root?

The hair follicle, hair bulb, dermal papilla, arrector pili muscle, and sebaceous glands. Signup and view all the answers

What is the hair follicle?

The tubelike depression or pocket in the skin or scalp that contains the hair root. Signup and view all the answers

What is the hair bulb?

The lowest part of a hair strand, it is the thickened club-shaped structure that forms the lower part of the hair root. Signup and view all the answers

What is the dermal papilla?

A small, cone-shaped elevation located at the base of the hair follicle that fits into the hair bulb. Signup and view all the answers

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?

The dermal papilla. Signup and view all the answers

What is the arrector pili muscle?

The small, involuntary muscle in the base of the hair follicle. Signup and view all the answers

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?

The hair cuticle, cortex, and medulla. Signup and view all the answers

What must an oxidation hair color, permanent waving solution, and chemical hair relaxer have to penetrate the cuticle layer?

An alkaline pH. Signup and view all the answers

What is the hair shaft that emerges?

A nonliving fiber composed of keratinized protein. Signup and view all the answers

What are the five major elements that make up human hair?

Carbon, oxygen, hydrogen, nitrogen, and sulfur. Signup and view all the answers

What are the five major elements that make up human hair referred to as?

The COHNS elements. Signup and view all the answers

What percent of the hair is made up of carbon?

51%. Signup and view all the answers

What percent of the hair is made up of oxygen?

21%. Signup and view all the answers

What percent of the hair is made up of hydrogen?

6%. Signup and view all the answers

What percent of the hair is made up of nitrogen?

17%. Signup and view all the answers

What percent of the hair is made up of sulfur?

5%. Signup and view all the answers

What are joined together end-to-end like pop beads?

Amino acids. Signup and view all the answers

What is the strong, chemical bond that joins amino acids?

Peptide bonds. Signup and view all the answers

What is a long chain of amino acids linked by peptide bonds called?

Polypeptide chains. Signup and view all the answers

What are long, coiled complex polypeptides made of amino acids?

Proteins. Signup and view all the answers

What is the spiral shape of a coil protein called?

A helix. Signup and view all the answers

What is a hydrogen bond?

A weak, physical, cross-link side bond that is easily broken by water or heat. Signup and view all the answers

How are hydrogen bonds broken?

By wetting the hair with water. Signup and view all the answers

When do hydrogen bonds reform?

When the hair dries. Signup and view all the answers

What is a salt bond?

A weak, physical, cross-link side bond between adjacent polypeptide chains. Signup and view all the answers

How are salt bonds broken?

By strong alkaline or acidic solutions. Signup and view all the answers

What is a disulfide bond?

A strong, chemical, side bond. Signup and view all the answers

How is the disulfide bond different from a hydrogen or salt bond?

It joins the sulfur atoms of two neighboring cysteine amino acids to create one cysteine. Signup and view all the answers

How are disulfide bonds broken?

By permanent waves and chemical hair relaxers that alter the shape of the hair. Signup and view all the answers

What breaks and reforms disulfide bonds?

Thio permanent waves and thio neutralizers. Signup and view all the answers

After hydroxide chemical hair relaxers break disulfide bonds what do they convert them to?

Lanthionine bonds. Signup and view all the answers

What refers to the shape of the hair strand and describes a straight, wavy, curly, or extremely curly?

The wave pattern. Signup and view all the answers

What is hair with a round cross-section?

Straight. Signup and view all the answers

What is hair with an oval to flattened cross-section?

Wavy or curly. Signup and view all the answers

What is hair with a flattened to flatten oval cross-section?

Extremely curly. Signup and view all the answers

What are the two types of hair found on the body?

Vellus and terminal. Signup and view all the answers

What is vellus hair?

Also known as lanugo hair, is short fine unpigmented and downy hair. Signup and view all the answers

What is terminal hair?

Long coarse pigmented hair found on the scalp, legs, arms, and bodies of males and females. Signup and view all the answers

Who does scalp hair grow faster on?

Women. Signup and view all the answers

What ages does scalp hair grow the most rapidly?

15 and 30. Signup and view all the answers

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?

4 to 5 years. Signup and view all the answers

What do recent measurements indicate that the average rate of hair loss is?

35 to 40 hairs per day. Signup and view all the answers

What is abnormal hair loss called?

Alopecia. Signup and view all the answers

What are the three most common types of abnormal hair loss?

Androgenic alopecia, alopecia areata, and postpartum alopecia. Signup and view all the answers

What is androgenic alopecia?

Also known as androgenetic alopecia, hair loss that is characterized by miniaturization of terminal hair that is converted into vellus hair. Signup and view all the answers

What is alopecia areata?

An autoimmune disorder that causes the affected hair follicles to be mistakenly attacked by a person's own immune system. Signup and view all the answers

How does alopecia areata begin?

With one or more small, round, smooth bald patches on the scalp. Signup and view all the answers

What is alopecia totalis?

Total scalp hair loss. Signup and view all the answers

What is alopecia universalis?

Total body hair loss. Signup and view all the answers

What is postpartum alopecia?

Temporary hair loss experienced at the end of pregnancy. Signup and view all the answers

What is canities?

The technical term for gray hair. Signup and view all the answers

What is hypertrichosis?

Also known as hirsutism, a condition of abnormal growth of hair. Signup and view all the answers

What is trichoptilosis?

The technical term for split ends. Signup and view all the answers

What is trichorrhexis nodosa?

The technical term for knotted hair. Signup and view all the answers

What is monilethrix?

The technical term for beaded hair. Signup and view all the answers

What is fragilitas crinium?

The technical term for brittle hair. Signup and view all the answers

What is pityriasis?

The technical term for dandruff. Signup and view all the answers

What is malassezia?

A naturally occurring fungus that is present on all human skin that causes the symptoms of dandruff when it grows out of control. Signup and view all the answers

What is pityriasis steatoides?

A more severe case of dandruff characterized by an accumulation of greasy or waxy scales mixed with sebum that sticks to the scalp in crusts. Signup and view all the answers

What is tinea?

The technical term for ringworm. Signup and view all the answers

What is tinea favosa?

Also known as tinea favus, is characterized by dry, sulfur-yellow, cup-like crusts on the skin called scutula. Signup and view all the answers

What are scabies?

A highly contagious skin disease caused by a parasite called a mite that burrows under the skin. Signup and view all the answers

What is pediculosis capitis?

The infestation of the hair and scalp with head lice. Signup and view all the answers

What is a furuncle?

The technical term for a boil. Signup and view all the answers

What is a carbuncle?

An inflammation of the subcutaneous tissue caused by staphylococci. Signup and view all the answers

What is hair texture?

The thickness, or diameter of the individual hair strand. Signup and view all the answers

What can hair texture be classified as?

Coarse, medium, or fine. Signup and view all the answers

What is hair density?

Measures the number of individual hair strands on one square inch of scalp. Signup and view all the answers

What is the average number of hairs on blond hair?

140,000. Signup and view all the answers

What is the average number of hairs on brown hair?

110,000. Signup and view all the answers

What is the average number of hairs on black hair?

108,000. Signup and view all the answers

What is the average number of hairs on red hair?

80,000. Signup and view all the answers

Healthy hair with a compact cuticle layer that is naturally resistant to being penetrated by moisture is referred to as?

Hydrophobic. Signup and view all the answers

What is porous hair that has a raised cuticle layer that easily absorbs moisture called?

Hydrophilic. Signup and view all the answers

What is a hair stream?

The hair flowing in the same direction, resulting from follicles sloping in the same direction. Signup and view all the answers

What is a whorl?

It occurs when hair leaves the follicles at an angle, resulting in a specific pattern of hair growth. Signup and view all the answers

What is a cowlick?

A particular pattern of hair streams on the forehead. Signup and view all the answers

Dry hair and scalp should be treated with products that contain what?

Moisturizers and emollients. Signup and view all the answers

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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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.