INTEGUMENTARY SYSTEM (LEC)

Question 1

-covers the entire body

-has a surface area of 1.2 to 2.2 square meters

-weighs 4–5 kg

-about 7% of total body weight in the average adult

-thickness - 1.5 to 4.0 millimeters

Answer 1

Skin

Question 2

skin has a surface area of

Answer 2

1.2 to 2.2 square meters

Question 3

skin weighs

Answer 3

4-5 kg

Question 4

skin is about what percentage of total body weight in the average adult

Answer 4

7%

Question 5

skin thickness is

Answer 5

1.5 to 4.0 millimeters

Question 6

the skin protects deeper tissues from

Answer 6

•Mechanical damage
•Chemical damage
•Bacterial damage
•Thermal damage
•Ultraviolet radiation
•Desiccation

Question 7

Functions of the skin

Answer 7

•Protects deeper tissues from:
- Mechanical damage
- Chemical damage
- Bacterial damage
- Thermal damage
- Ultraviolet radiation
- Desiccation
•Aids in heat regulation
•Aids in excretion of urea and uric acid
•Synthesizes vitamin D

Question 8

Cells of the Epidermis

Answer 8

•Keratinocytes
•Melanocytes
•Dendritic cells
•Tactile cells

Question 9

produce keratin, the fibrous protein that helps give the epidermis its protective properties

Answer 9

Keratinocytes

Question 10

the fibrous protein that helps give the epidermis its protective properties

Answer 10

keratin

Question 11

most epidermal cells are

Answer 11

Keratinocytes

Question 12

keratinocytes arise from

Answer 12

stratum basale

Question 13

undergo almost continuous mitosis in response to prompting by epidermal growth factor, a peptide produced by various cells throughout the body

Answer 13

Keratinocytes

Question 14

Millions of dead keratinocytes rub off every day, giving us a
totally new epidermis every

Answer 14

25 to 45 days

Question 15

cell production and keratin formation is accelerated in body areas regularly subjected to _____________, such as the hands and feet

Answer 15

friction

Question 16

cell production and keratin formation is accelerated in body areas regularly subjected to friction, such as the

Answer 16

hands and feet

Question 17

the spidershaped epithelial cells that synthesize the pigment melanin

Answer 17

Melanocytes

Question 18

melanocytes accumulates in membrane-bound granules called

Answer 18

melanosomes

Question 19

are transferred to nearby keratinocytes

Answer 19

melanin

Question 20

accumulate on the superficial, or “sunny,” side of the keratinocyte nucleus, forming a pigment shield that protects the nucleus from the damaging effects of ultraviolet (UV) radiation in sunlight

Answer 20

melanin granules

Question 21

star-shaped cells that arise from bone marrow and migrate to the epidermis

Answer 21

dendritic cells

Question 22

dendritic cells are also called

Answer 22

Langerhans cells

Question 23

ingest foreign substances and are key activators of our immune system

Answer 23

dendritic cells

Question 24

star-shaped dendritic cells arise from

Answer 24

bone narrow

Question 25

present at the epidermal-dermal junction

Answer 25

Tactile (Merkel) cells

Question 26

shaped like a spiky hemisphere

Answer 26

Tactile (Merkel) cells

Question 27

each tactile cell is intimately associated with a

Answer 27

disc-like sensory nerve ending

Question 28

functions as a sensory receptor for touch.

Answer 28

Tactile (Merkel) disc

Question 29

Two distinct layers of the skin

Answer 29

Epidermis and dermis

Question 30

made up of stratified squamous epithelium, hardened by keratin

Answer 30

Epidermis

Question 31

making up the bulk of the skin, is a tough, leathery layer composed mostly of fibrous connective tissue, vascularized

Answer 31

Dermis

Question 32

The subcutaneous tissue just deep to the skin is known as the

Answer 32

hypodermis

Question 33

Layers of the Epidermis

Answer 33

Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum

Question 34

deepest epidermal layer

Answer 34

Stratum basale

Question 35

consists of a single row of stem cells—a continually renewing cell population

Answer 35

Stratum basale

Question 36

a continually renewing cell population

Answer 36

stem cells

Question 37

Each time one of these basal cells divides, one daughter cell is pushed into the cell layer just above to begin its specialization into a

Answer 37

mature keratinocyte

Question 38

10-25% of cells in the stratum basale are

Answer 38

melanocytes

Question 39

contain a weblike system of intermediate filaments, mainly tension-resisting bundles of pre-keratin filaments, which span their cytosol to attach to desmosomes

Answer 39

Stratum spinosum

Question 40

Scattered among the keratinocytes (in stratum spinosum) are

Answer 40

melanin granules and dendritic cells