Ch 6: Integumentary System

Question 1

What are the functions of the skin

Answer 1

protection against micro-organisms and water-damage (keratin); regulation of body temperature; excretion of waste materials; synthesis of Vitamin D; respond to stimuli

Question 2

Epidermis

Answer 2

outer most layer; stratified squamous epi.; avascular; up to 5 sublayers

Question 3

what are the 5 sublayers of the epidermis

Answer 3

1. stratum basale or stratum germinativum (bottom layer; rests on basement membrane; single layer of cuboidal or columnar cells; much mitosis);
2. stratum spinosum (several layers; cells have delicate “spines” that protrude from their surface to inter-lock cells; creates a barrier; mitosis);
3. stratum granulosum (usually 2 to 4 cells thick; synthesis of keratohyaline, which will migrate to surface and become keratin);
4. stratum lucidum (found only in palms and soles; flat cells; synthesis of eleidin, which protects against UV damage);
5. stratum corneum (surface layer; very flat, dead cells; cells are constantly shed; offers protection against miro-organisms and dehydration; covered by keratin, which also protects skin)

Question 4

dermis

Answer 4

middle layer; thicker layer; 2 sublayers

Question 5

what are the 2 sublayers of the dermis

Answer 5

1. papillary layer (directly below epidermis; loose C.T.; contains papillae or folds, which are your fingerprints; vascular; nerve endings;
2. reticular layer (deeper layer; dense irregular C.T.; vascular; glands; hair follicles; nerve endings)

Question 6

hypodermis/ subcutaneous layer

Answer 6

deepest layer; adipose tissue; vascular; glands; cushions and supports

Question 7

what are the 2 types of sudoriferous glands (sweat glands)

Answer 7

1. eccrine gland

2. apocrine gland/ odiferous gland

Question 8

eccrine glands

Answer 8

(small; distributed over nearly the entire body; none found in eardrums, nail beds, or margins of lips; simple coiled tubular; respond to heat, regulate temperature);

Question 9

apocrine glands/ odiferous glands

Answer 9

(larger and more deeply situated; locations include armpits; dark region around nipples; anal and genital regions; become active at puberty; can respond to stress; release an “odor”; not for temperature regulation)

Question 10

sebaceous glands (oil glands)

Answer 10

simple, branched alveolar glands; lubrication and protection; produce sebum; found all over the body, usually at base of hair follicle; not found in palms and soles

Question 11

minor first degree burn

Answer 11

affects less than 10% of the body; epidermis damaged;

Mild swelling; reddening; some pain; injured cells peel off and skin heals without scarring, usually within 2 weeks

Question 12

serious second degree burn

Answer 12

affects more than 15% of adult body or more than 10%
of child body; epidermis and part of dermis damaged; new skin may regenerate; red or mottled appearance; swelling; greater pain; blisters may occur

Question 13

severe third degree burn

Answer 13

affects more than 20% of the body; requires prompt
medical attention; all skin layers damaged; deep tissue destruction; skin cannot regenerate; surgery and skin grafts necessary; white or charred appearance; severe loss of body fluids; usually due to some catastrophic event (fire / chemical)

Question 14

basal cell epithelioma skin cancer

Answer 14

generally appears on the face where sebaceous
glands and hair follicles are abundant; most frequent in males over 40; three types of lesions are typical (noduloulcerative lesions – small and pink during early stage; enlarge and become ulcerative and scaly…..superficial basal cell epithelioma – erupt on back and chest; lightly pigmented and slightly elevated……sclerosing basal cell epithelioma – waxy, yellowish-white patches that appear on head and neck)

Question 15

squamous cell carcinoma skin cancer

Answer 15

usually appear as pre-malignant lesions on face,

ears, mouth, and lips; most common in males over 60

Question 16

malignant melanoma skin cancer

Answer 16

involves pigment-producing melanocytes; usually starts
as small dark growth resembling moles; gradually become larger, change color, ulcerate, and bleed easily; most common in women after puberty (pregnant women must be careful with sun exposure, because hormonal changes may increase risk of Melanoma)

Question 17

hair

Answer 17

is found all over the body surface, except the palms and soles; consists of 3 parts:

1. medulla
2. cortex
3. cuticle

Question 18

medulla

Answer 18

the central region

Question 19

cortex

Answer 19

surrounds the medulla; contains pigments that give rise to hair color

Question 20

cuticle

Answer 20

the outer protective layer, abrasion of the cuticle results in ‘split ends’

Question 21

follicle

Answer 21

is a structure from epithelial tissue (internal and external root sheath) which rests on a thick basement membrane (glassy membrane) and dermal tissue (C.T. root sheath); a small portion of the C.T. root sheath protrudes into the hair bulb and provides nutrition to the growing hair, is called the Papilla.

Question 22

root

Answer 22

is the portion of hair enclosed within the follicle

Question 23

shaft

Answer 23

is the portion of hair protruding from the scalp surface

Question 24

hair bulb

Answer 24

is a collection of well-nourished germinal epithelial cells at the basal end of the follicle; as the daughter cells are pushed further away from the growing region, they die and become keratinized; thus the bulk of the hair shaft, like the bulk of the epidermis, is dead material

Question 25

arrestor pili muscle

Answer 25

are small bands of smooth muscle cells connecting each hair follicle to the papillary layer of the dermis; when these muscles contract (during cold or fright), the slanted hair follicle is pulled up-right, dimpling the skin surface with goose bumps

Question 26

hair growth

Answer 26

hair cycle consists of three developmental stages:

1. anagen stage
2. catagen stage
3. telogen stage

Question 27

anagen stage

Answer 27

a) Stem cells from the bulge in the follicle multiply and travel downward, pushing the dermal papilla deeper into the skin and forming the epithelial root sheath
b) Root sheath cells directly above the dermal papilla form the hair matrix; sheath cells transform into hair cells, which synthesize keratin and then die as they are pushed upward away from the papilla
c) The new hair grows up the follicle, often alongside an old club hair left from the previous cycle

Question 28

catagen stage

Answer 28

a) Mitosis in the hair matrix ceases and sheath cells below the bulge die
b) The follicle shrinks and the dermal papilla draws up toward the bulge
c) The base of the hair keratinizes into a hard club and the hair, now known as club hair, loses its anchorage
d) Club hairs are easily pulled out by brushing the hair and the hard club can be felt at the hair’s end
e) When the papilla reaches the bulge, the hair goes into a resting period called the Telogen Stage

Question 29

nails

Answer 29

are derivatives of the epidermis;
are composed of the following parts:
1. body
2. free edge
3. root
4. nail folds
5. eponychium
6. nail bed
7. nail matrix
8. lunula

Question 30

body

Answer 30

the visible attached portion

Question 31

free edge

Answer 31

the portion of the nail that grows out away from the body

Question 32

root

Answer 32

the part that is embedded in the skin and adheres to an epithelial nail bed

Question 33

nail folds

Answer 33

skin folds that overlap the borders of the nail

Question 34

eponychium

Answer 34

the thick proximal nail fold commonly called the cuticle

Question 35

nail bed

Answer 35

an extension of the stratum basale beneath the nail

Question 36

nail matrix

Answer 36

the thickened proximal part of the nail bed containing germinal cells responsible for nail growth; as the matrix produces nail cells, they become heavily keratinized and die; thus nails, like hair are mostly nonliving material

Question 37

lunula

Answer 37

the proximal region of the thickened nail matrix, which appears as a white crescent; it is located at the free edge of the nail; the rest of the nail appears pink, due to underlying blood vessels in the underlying dermis