Accessory Structure of the Skin

Question 1

structure of hair

Answer 1

columns of dead, keratinized cells that are fused together. shaft, root, bulb, papilla

Question 2

function of hair.

Answer 2

covers all surfaces of the body except palms, soles, eyelids, lips, and nipples.

Question 3

function of scalp hair.

Answer 3

reduces heat loss and provides protection from ultraviolet radiation

Question 4

function of eyebrows

Answer 4

enhance facial expression and non-verbal communications.

Question 5

function of eyelashes

Answer 5

shield eyes from rain and windblown debris

Question 6

function of guard hairs

Answer 6

prevents foreign particles from entering the nostrils or ear canals.

Question 7

shaft.

Answer 7

portion of a hair above the skin surface.

Question 8

root

Answer 8

deep to the shaft and is surrounded by the tube called the follicle.

Question 9

bulb

Answer 9

swelling at the base of the follicle from which hair originates.

Question 10

papilla

Answer 10

contains blood vessels to nourish hair.

Question 11

layers in the hair.

Answer 11

inner medulla, cortex, cuticle.

Question 12

inner medulla.

Answer 12

contains air spaces. (not solid)

Question 13

cortex

Answer 13

densely packed keratinized cells

Question 14

cuticle

Answer 14

single layer of overlapping scaly cells as cuticles wear away, keratin fibrils spill out of cortex and medulla causing ‘split-ends’ to develop.

Question 15

hair texture.

Answer 15

related to cross-sectional shape of the hairs.

Question 16

hair color

Answer 16

due to the type and amount of pigment in each hair.

Question 17

hair shafts are flat and ribbon-like

Answer 17

kinky hair texture.

Question 18

hair shafts are oval

Answer 18

silky and wavy hair texture.

Question 19

hair shafts are round

Answer 19

straight/ coarse hair texture.

Question 20

hair growth cycle.

Answer 20

1. stem cells from the follicle multiply and push the papilla deeper into the skin
2. cell in the root sheath transform into hair cells that synthesize keratin.
3. hair goes into a resting phase and eventually fall out.

Question 21

how much does scalp hair grow.

Answer 21

1mm every three days. 10-18 cm every year (7in).

Question 22

alopecia

Answer 22

hair growth slow down around the age of 40 (hair loss) because of aging, disease, or poor nutrition or medical treatment.

Question 23

pattern baldness

Answer 23

genetic condition expressed in individuals with high testosterone.

Question 24

arrector pili muscle

Answer 24

smooth muscle and is associated with each hair.

Question 25

“goose bumps”

Answer 25

cold temp., fright, or emotional stress can cause these muscles to contract and pull a hair into a vertical position.

Question 26

description

Answer 26

plates of hard, keratinized cells that form protective coverings over the dorsal surface of the terminal portion of the fingers and toes.

Question 27

free edge.

Answer 27

portion of the nail that extends beyond the end of the digit.

Question 28

lunule

Answer 28

small white area at the proximal end of the nail body

Question 29

cuticle

Answer 29

dead epidermis that covers the proximal end of the nail (protection of nail matrix).

Question 30

what causes nail to grow.

Answer 30

mitosis from the nail matrix at a rate of 1 mm per week.

Question 31

structure of sebaceous (oil) glands.

Answer 31

usually connected to hair follicles, although some of them open directly to the surface of the skin.

Question 32

function of sebum

Answer 32

keep hair from dying out and turning brittle, keep skin soft and moist to inhibit growth of certain bacteria. secreted from oil glands.

Question 33

what happens when there is accumulation of sebum

Answer 33

in facial sebaceous glands causes blackheads which can lead to the formation of pimples if they become infected with bacteria.

Question 34

what does the Sudoriferous (sweat) gland do?

Answer 34

produces a mixture of water, salts, and organic compounds.

Question 35

function of sweat?

Answer 35

regulates body temperature by providing a cooling mechanism and also eliminates urea, lactic acid, ammonia, and some drugs from the body “precipitation.”

Question 36

Two types of sweat gland.

Answer 36

eccrine and apocrine.

Question 37

Define eccrine.

Answer 37

3 to 4 million distributed through-out the skin, palms, soles, forehead, produce watery perspiration.

Question 38

Define apocrine

Answer 38

located in the armpits, pubic area, breast and beard area of mature males where their ducts lead to nearby hair follicles rather than to the surface of the skin.

Question 39

How do apocrine differ from eccrine?

Answer 39

apocrine produce viscous perspiration.
Apocrine does not develop till puberty and response to emotional stress and sexual arousal
females have enlarge glands that shrink during menstrual cycle.