Hair Theory

Question 1

Trichology def

Answer 1

Study of hair

Question 2

Main purposes of hair

Answer 2

Adornment
Protection from heat, cold, and injury
Sensory perception

Question 3

Hair is derived from the ______

Answer 3

Epidermis

Question 4

Three segments of the hair follicle

Answer 4

Bulb
Isthmus
Infundibulum

Question 5

Bulb segment, parts, and description

Answer 5

Lower segment

Dermal papilla
Root sheath
Germinal matrix

Extends from base of follicle to insertion of arrector pili muscle

Question 6

Isthmus segment, parts, and description

Answer 6

Middle segment

Arrector pili muscle
Glands

Extends from insertion of arrector pili muscle to entrance of sebaceous gland duct

Question 7

Infundibulum segment, parts, and description

Answer 7

Upper segment

Hair strand (hair shaft)

Extends from the entrance of sebaceous gland duct to opening of the follicle; filled with sebum

Question 8

Dermal papilla def

Answer 8

A mass of loose connective tissue located at base of the hair follicle

Question 9

Germinal matrix cells def

Answer 9

Tiny capillaries (small blood vessels) that supply nourishment to the cells around it

Question 10

Root sheath def

Answer 10

Inner and outer portions that help form growing hair

Question 11

Outer root sheath description and contains?

Answer 11

Continuation of the basale layer
Surrounds the inner root sheath
Remains static
Serves as storage for stem cells

Melanocytes
Langerhans cells
Merkel cells

Question 12

Inner root sheath description

Answer 12

Structure in the lower part of the hair follicle
Surrounds and protects growing hair
Helps hair take a shape

Question 13

Three layers of the inner root sheath with defs

Answer 13

Henie’s layer - outermost layer of inner root sheath; single layer of cube-like cells with clear, flattened nuclei

Huxley’s layer - between cuticle and Henie’s layer; contains 1-2 layers of flattened epithelial cells

Cuticle layer - lies in the center; forms channel for growing hair; anchors hair in place

Question 14

Vellus hair def

Answer 14

Peach fuzz

Question 15

Capilli hair def

Answer 15

Hair on scalp (cap-calp)

Question 16

Barba hair def

Answer 16

Beard hair (think barber)

Question 17

Cilia hair def

Answer 17

Eyelashes

Question 18

Supercillia hair def

Answer 18

Eyebrows

Question 19

lanugo hair def

Answer 19

Hair at birth

Question 20

Terminal hair def

Answer 20

Dark, coarse hair

Question 21

Which stage is the 1st and longest stage of hair growth

Answer 21

Anagen; active stage

Question 22

Which is the 2nd and shortest stage of hair growth

Answer 22

Catagen; transition stage

Question 23

What is the 3rd stage of hair growth and what is it called/known as

Answer 23

Telegen; resting stage

Question 24

What is the name of the area of cells around the dermal papilla

Answer 24

Germinal matrix

Question 25

Arrector pili muscle def

Answer 25

Isthmus or middle segment of the follicle

Question 26

Arrector pili muscle description

Answer 26

Extends from cells in the dermis to attach to the follicle just below the sebaceous gland and causes hair to stand up on end when a person is scared or cold

Question 27

Hair root def

Answer 27

Portion of hair inside the hair follicle under the skin’s surface

Question 28

Hair strand def

Answer 28

Portion of hair that extends above the skins surface

Question 29

Keratinization def

Answer 29

Process where cells change their shape, dry out, and form keratin protein; once keratinized, cells that form the hair strand are no longer alive

Question 30

3 parts of the hair strand

Answer 30

Medulla Cortex Cuticle

Question 31

Medulla def

Answer 31

Central core of the hair strand; also called the pith or marrow; often absent in fine or very fine hair

Question 32

Cortex def

Answer 32

Second layer, consists of unique protein structures; gives hair pigment and strength/flexibility

Question 33

Cuticle def

Answer 33

Outer covering of the hair strand; made up of overlapping layers of transparent scales

Question 34

Stratum basal layer “steps” (5)

Answer 34

1. In fetal life, the hair follicle forms from a cluster of cells in the upper layer of skin 2. The cluster of cells is called the “primitive hair germ”; it needs nourishment to grow into a fully developed hair follicle 3. To get nourishment, the primitive hair germ works its way down into the lower (dermal) layer 4. As the primitive hair germ works its way down, the cell cluster pulls the upper layer down with it creating a follicle 5. At the base of the hair follicle is a large structure called the “papilla” which supplies nourishment to the hair bulb

Question 35

Shapes of a follicle

Answer 35

Round Oval Elliptical

Question 36

The shape of the follicle will determine the shape of the _______as it grows from the follicle

Answer 36

Hair strand

Question 37

A round follicle will make what hairstrand shape

Answer 37

Straight hair

Question 38

An oval follicle will create what hairstrand shape

Answer 38

Wavy or curly hair

Question 39

Elliptical follicle will create what hairstrand shape

Answer 39

Tightly curled hair

Question 40

Anagen stage description

Answer 40

Active or growing stage Each hair bulb has attached to a root sheath On average, 90% of hair is in this stage (scalp lasts 2-6 years in anagen) Hair color is darker

Question 41

Catagen stage description

Answer 41

Brief transitional period when all cell division stops Shortest of the hair growth cycle Dermal papilla breaks away; lower end of the hair comes loose from the base of the follicle

Question 42

Telogen stage description

Answer 42

Resting stage Hair bulb has no attached root sheath Hair falls out On average, 10-15% of hair is in this stage

Question 43

2 factors that affect hair growth

Answer 43

Hirsutism Hypertrichosis

Question 44

Hirsutism possible cause and def

Answer 44

Polycystic ovary syndrome (PCOS) and Cushing syndrome Excessive amounts of terminal hair found in women in areas of the body where men usually get hair: face (above the upper lip and on the chin), back, abdomen, and chest Can affect both men and women

Question 45

Hypertrichosis possible cause and def

Answer 45

Ambras syndrome Abnormal coverage of hair on areas of the body where normally only lanugo or baby-fine hair appears

Question 46

The average rate of human hair growth

Answer 46

1/2” (1.25cm) per month

Question 47

Eyebrow and eyelash hair is replaced how often

Answer 47

4–5 months

Question 48

Melanin is found mainly in the ______

Answer 48

Cortex; the hairstrand’s second layer

Question 49

The natural coloring process

Answer 49

Melanocytes produce melanosomes, which contain the pigment melanin

Question 50

Melanin def

Answer 50

Produced my melanocytes- cells that exist among the dividing cells within the hair bulb

Question 51

Melanocytes def

Answer 51

rest near the hair bulb’s nourishment center, the dermal papilla, and form bundles of a pigment protein complex called melanosomes

Question 52

Two types of melanin

Answer 52

Eumelanin - brown/black Pheomelanin - red/yellow

Question 53

What influences the resulting hair color

Answer 53

The amount, size, and distribution of one or both of the melanin types

Question 54

If the amount of pheomelanin is very concentrated and near the cuticle layer, the hair color will appear more _____

Answer 54

Red

Question 55

Lighter hair has melanin only in the

Answer 55

Cortex

Question 56

Gray hair is caused by

Answer 56

Reduced color pigment (melanin) in the cortex kayaker of the hair