Ch. 5-7 Hair

Question 1

epidermal derivatives

Answer 1

structures that originate from epidermis during development; hair follicles, sebaceous, sweat glands, and nails.

Question 2

Hair

Answer 2

Non-living structures formed in organs called hair follicles

FUNCTIONS:

1. Protects and insulates
2. Guards against particles and insects
3. Sensory receptors

Question 3

Hair follicle

Answer 3

• Organ
• Located in the dermis
• produces non-living hairs
• wrapped in dense connective tissue sheath
• base surrounded by sensory nerves (root hair plexus)

Question 4

root hair plexus

Answer 4

sensory nerves that surround the base of each hair follcile

Question 5

arrector pili

Answer 5

• involuntary smooth muscle
• extends from papillary layer of dermis to the connective tissue sheath surrounding the hair follicle
• Causes hair to stand up; goose bumps

Question 6

hair root

Answer 6

• portion that anchors hair to skin
• begins at hair bulb and extends distally to the point at which the internal organization of the hair is complete (about halfway to skin surface)

Question 7

hair shaft

Answer 7

portion that can be seen on the surface. Extends from hair root (halfway point) to exposed tip of the hair

Question 8

club hair

Answer 8

• Term for hair at the end of the growth cycle
• Not growing
• Attached to inactive follicle
  
  • The follicle gets smaller until the connections between the hair matrix and the club hair root break down.

Question 9

Stages of the hair growth cycle

Answer 9

Anagen - growth (2-7 years)

Catagen - transition (2-3 weeks)

Telogen - restive (2-3 months). Bulb is gone.

Question 10

alopecia

Answer 10

baldness

Many causes; senescecent hair follicle can be caused by telomer shortening.

Question 12

hair bulb

Answer 12

• a mass of epitheleal cells that forms a cap that surrounds the hair papilla
• superficial cells are responsible for producing hair

Question 13

hair papilla

Answer 13

• a peg of connective tissue containing capillaries and nerves
• contains melanocytes for hair pigment

Question 14

hair matrix

Answer 14

• layer superficial cells of the hair bulb that are responsible for producing hair
• basal cells near the center divide, producing daughter cells pushed to the surface

Question 15

medulla

Answer 15

• Core of hair; formed by daughter cells closest to the center of the hair matrix

Question 16

cortex

Answer 16

middle layer of of the hair matrix

Question 17

cuticle

Answer 17

cells at the edges of the hair matrix

Question 18

Hair Follicle Structure

Answer 18

1. Internal root sheath
2. External root sheath
3. Glassy membrane
4. Connective tissue sheath

Question 19

lanugo

Answer 19

hairs that first appear ~3 months of embryonic development. Fine and unpigmented.

Question 20

vellus hairs

Answer 20

1. Soft, fine
2. covers body surface

Question 21

terminal hairs

Answer 21

1. heavy, pigmented
2. head, eyebrows, lashes
3. other parts converted from vellus hairs after puberty

Question 22

• Organ
• Located in the dermis
• produces non-living hairs
• wrapped in dense connective tissue sheath
• base surrounded by sensory nerves (root hair plexus)

Answer 22

Hair follicle

Question 23

sensory nerves that surround the base of each hair follcile

Answer 23

root hair plexus

Question 24

• involuntary smooth muscle
• extends from papillary layer of dermis to the connective tissue sheath surrounding the hair follicle
• Causes hair to stand up; goose bumps

Answer 24

arrector pili

Question 25

• portion that anchors hair to skin
• begins at hair bulb and extends distally to the point at which the internal organization of the hair is complete (about halfway to skin surface)

Answer 25

hair root

Question 26

portion that can be seen on the surface. Extends from hair root (halfway point) to exposed tip of the hair

Answer 26

hair shaft

Question 27

• Term for hair at the end of the growth cycle
• Not growing
• Attached to inactive follicle
  
  • The follicle gets smaller until the connections between the hair matrix and the club hair root break down.

Answer 27

club hair

Question 28

baldness

Many causes; senescecent hair follicle can be caused by telomer shortening.

Answer 28

alopecia

Question 29

• a mass of epitheleal cells that forms a cap that surrounds the hair papilla
• superficial cells are responsible for producing hair

Answer 29

hair bulb

Question 30

• a peg of connective tissue containing capillaries and nerves
• contains melanocytes for hair pigment

Answer 30

hair papilla

Question 31

• layer superficial cells of the hair bulb that are responsible for producing hair
• basal cells near the center divide, producing daughter cells pushed to the surface

Answer 31

hair matrix

Question 32

• Core of hair; formed by daughter cells closest to the center of the hair matrix

Answer 32

medulla

Question 33

middle layer of of the hair matrix

Answer 33

cortex

Question 34

cells at the edges of the hair matrix

Answer 34

cuticle

Question 35

hairs that first appear ~3 months of embryonic development. Fine and unpigmented.

Answer 35

lanugo

Question 36

1. Soft, fine
2. covers body surface

Answer 36

vellus hairs

Question 37

1. heavy, pigmented
2. head, eyebrows, lashes
3. other parts converted from vellus hairs after puberty

Answer 37

terminal hairs