CHAPTER 5

Question 1

Skin

Answer 1

body’s largest organ. 2 layers, epidermis/dermis within skin plus one nearby.

Question 2

Epidermis

Answer 2

epithelium of skin- superficial region outtermost protective shield of body

Question 3

Tissue type

Answer 3

keratinized stratified squamos epithelium 4 cell types 4-5 layers

Question 4

Vascularity

Answer 4

Epidermis is avascular- nutrients diffuse from deeper connective tissue

Question 5

cells of epidermis

Answer 5

superficial cells are dead no nuclei- sparse nerve endings

Question 6

keratinocytes

Answer 6

(no nuclei) synthesize keratin vast majority of epidermal cells/ found in many layers

Question 7

keratinocyte- function

Answer 7

gives epidermis its productive properties

Question 8

keratinocyte- location

Answer 8

keratinized stratified squamos epithelium- arise stratum basale pushed up as grow due in stratus corneum

Question 9

melanocytes

Answer 9

spider shaped epithelial cells make melanin a brown to black pigment

Question 10

melanocytes- function

Answer 10

taken up by keratinocytes and used to protect their DNA from ultraviolet radiation

Question 11

melanocytes- location

Answer 11

stratum basale

Question 12

dendritic cells (Langerhans)

Answer 12

star shaped cells, immune surveilance.

Question 13

dendritic cells- function

Answer 13

protect from microbes, toxins, and pathogens. ingest foreign substances, activate immune system

Question 14

dendritic cells- location

Answer 14

stratum spinosum, stratum granulosum, (2 middle layers of epidermis) arise bone marrow migrate to epidermis

Question 15

Tactile cells (Merkel)

Answer 15

touch receptors that join with nerves. shaped like spiky hemispheres

Question 16

Tactile cells- function

Answer 16

sensory receptors for touch, associated with sensory nerve ending

Question 17

Tactile cells- location

Answer 17

stratum basale

Question 18

Layers of the Epidermis

Answer 18

variation in epidermal thickness determines thick or thin

Question 19

Stratum basale

Answer 19

germinating layer- attached to dermis, single row of stem cells

Question 20

Stratum basale- cells

Answer 20

melanocytes, keratinocytes, and tactile (merkel)

Question 21

Stratum basale- function

Answer 21

regenerates new basal cells

Question 22

Stratum spinosum

Answer 22

prickly layer- several layers thick

Question 23

Stratum spinosum- cells

Answer 23

keratinocytes and Langerhans (dendritic)

Question 24

Stratum spinosum- function

Answer 24

cells contain thick bundles of intermediate filament that are made of pre keratin

Question 25

stratum granulosum

Answer 25

3-6 cell layers thick

Question 26

stratum granulosum cells

Answer 26

keratinocytes (organelles deteriorating) cytoplasm full of lamellated granules and keratohyaline granules

Question 27

Stratum lucidum

Answer 27

visible only in thick skin, thin translucent band or zone

Question 28

Stratum lucidum cells

Answer 28

2-3 rows of clear flat dead keratinocytes

Question 29

Stratum lucidum- function

Answer 29

stick corneum to granulosum, provide little protection

Question 30

Thick skin

Answer 30

areas of high abrasion, epidermis 5 strata (layers) and thicker stratum corneum. palm, fingertips, soles of feet

Question 31

Thin skin

Answer 31

rest of body, 4 strata

Question 32

Stratum corneum

Answer 32

20-30 cell layers thick make up 3/4 epidermal thickness, outtermost layer

Question 33

Stratum corneum- cells

Answer 33

dead keratinocytes

Question 34

Stratum corneum- function

Answer 34

protect from abrasion, penetration, and dehydration

Question 35

Dermis- beneath epithelium

Answer 35

second major skin region, strong flexible connective tissue contains nerve fibers, blood and lymphatic vessels, hair follicles, and oil/ sweat glands

Question 36

Dermis vascularity

Answer 36

rich supply of blood vessels

Question 37

dermal layers

Answer 37

further subdivided into 2 layers papillary and reticular

Question 38

Papillary layer

Answer 38

thin superficial layer

Question 39

Tissue type

Answer 39

areolar connective tissue contain collagen and elastic fibers

Question 40

additional structures

Answer 40

blood vessels

Question 41

Dermal papillae

Answer 41

peg like projections contain capillary loops, blood vessels, free nerve endings, and meisners corpuscles (tactile)

Question 42

Dermal ridges

Answer 42

in thick skin, large mounds found under the papillae

Question 43

Epidermal ridges

Answer 43

formed on the overlying epidermis due to the dermal ridges, referred to as friction ridges, enhance the griping ability. ridge patterns are genetically determined and unique. when sweat pores open along their crest our fingerprints leave identifying films of sweat/fingerprint

Question 44

Capillary loops

Answer 44

blood carrying vessels allow for exchange to occur (nutrients-wastes)

Question 45

Free nerve endings

Answer 45

serve as pain receptors

Question 46

meissners corpuscles

Answer 46

touch receptors

Question 47

reticular layer- irregular dense fibrous connective tissue

Answer 47

deeper/ accounts for 80percent of dermal thickness, has cutaneous plexus and flexure lines

Question 48

cutaneous plexus

Answer 48

network of blood vessels which nourishes reticular layer

Question 49

flexure lines

Answer 49

dermal folds that occur at or near joints allowing for flexibility

Question 50

hypodermis- connective tissue (adipose)

Answer 50

nearby layer known as superficial fascia, connective tissue just underneath skin. mostly made up of adipose subcutaneous tissue fund just deep to skin. stores fat and anchors skin to muscle loosely so skin can move

Question 51

skin color

Answer 51

3 major pigments determine skin color

Question 52

melanin

Answer 52

only one made in skin by melanocytes. subtypes eumelanin- brownish/black, phemelanin- reddish/yellow skin tones vary due to distribution of melanin (not # melanocytes)

Question 53

carotene

Answer 53

yellow to orange pigment found in certain plant foods/ carrots, concentrates in stratum corneum

Question 54

hemoglobin

Answer 54

a pigment which contains oxygen and found in red blood cells (pale look lack of hemoglobin)

Question 55

appendages of the skin

Answer 55

cyanosis- blueness