13. Integumentary Sytem

Question 1

Integumentary consists of

Answer 1

Skin (epidermis and dermis)
Subcutaneous tissue (hypodermis)
Appendages (glands, hair, nails)

Question 2

What is skin?

Answer 2

Largest organ of the body
Varies in thickness across body regions
Composed of 2 layers: epidermis and dermis
Holds a variety of appendages important for its function

Question 3

Functions of skin

Answer 3

Protection
Temperature regulation
Excretion
Vitamin D production
Sensory reception

Question 4

How does skin regulate temperature

Answer 4

Capillaries and sweat glands regulate heat loss

Question 5

How does skin excrete waste

Answer 5

Excrete urea, salts, and water through sweat

Question 6

How does skin produce vitamin D

Answer 6

Cells use UV radiation to synthesize vitamin D

Question 7

Characteristics of the epidermis

Answer 7

Superficial layer of skin
Consists of keratinized stratified squamous epithelium
Primary cell type= keratinocytes
Dead cells rub off and are replaced
There are thick and thin skin

Question 8

What are the surface cells of the epidermis

Answer 8

Dead keratinocytes full of protective protein, keratin

Question 9

What are keratinocytes?

Answer 9

Produce keratin, primary cell type of epidermis

Question 10

Number of layers of thick and thin skin

Answer 10

Thick: 5 layers ( hands & feet)
Thin: 4 layers

Question 11

Layers of the epidermis

Answer 11

Stratum basale, stratum spinosum, stratum granulosum, stratum corneum, and stratum lucidum (only in thick skin)

Question 12

Characteristics of stratum basale

Answer 12

Deepest layer, attached to dermis
Single row of stem cells undergoing mitosis
Includes tactile epithelial cells (Merkel cells) and melanocytes

Question 13

What are tactile epithelial cells (Merkel cells)

Answer 13

Cells attached to nerve ending in stratum basale for touch sensation

Question 14

What are melanocytes

Answer 14

Produce melanin and gives skin color
Absorbed by keratinocytes, protect from radiation

Question 15

Characteristics of stratum spinosum

Answer 15

Several cell layers thick
Mitosis occurs but less that basal layer
Cells contain thick bundles of intermediate filaments with pre-keratin to resist tension
Include dendritic cells

Question 16

What are dendritic cells?

Answer 16

Part of immune system for recognizing foreign proteins

Question 17

Characteristics of stratum granulosum

Answer 17

1-5 flat cell layers
Cells contain pre-keratin and granules (i.e. granular layer)
Cells far from nutrients supplied by capillaries in dermis, organelles start to breakdown

Question 18

What are granules

Answer 18

Help form keratin
Produce glycolipids to help prevent water loss

Question 19

Characteristics of stratum corneum

Answer 19

External layer, many cells thick
Consists of dead keratinocytes, filled with keratin
Protects deeper layers from abrasions
Waterproof from glycolipids between cells
Cells are shed continuously

Question 20

Characteristics of stratum lucidum

Answer 20

Only in thick skin
Between stratum granulosum and stratum corneum
Few rows of flat, dead keratinocytes
Cells identical to bottom of stratum corneum

Question 21

Characteristics of dermis

Answer 21

Deep layer of the skin
Made of connective tissue that resists tension in all directions and is vascular & innervated
Same as hide used to make leather
2 layers: papillary dermis and reticular dermis

Question 22

Characteristics of papillary dermis

Answer 22

Superficial layer of dermis
Mostly areolar connective tissue
Contains projections into epidermis (dermal papillae)
Larger dermal ridges create ridges of the epidermis on palms and soles of feet (e.g., fingerprints)

Question 23

What to dermal papillae do

Answer 23

Increase surface area for exchange of materials with epidermis

Question 24

Characteristics of reticular dermis

Answer 24

Deepest layer of dermis
Dense irregular connective tissue
Dense network of collagen and elastic fibers give strength and stretching properties
Has rich supply of nerves and vessels

Question 25

What do dermal vessels do?

Answer 25

Blood vessels supply nutrients and regulate temperature When hot, dermal vessels open to allow for cooling (become flush)

Question 26

What pigments are involved in skin color

Answer 26

Melanin, carotene, hemoglobin

Question 27

Characteristics of melanin

Answer 27

Primary pigment of skin Range from yellow to black Generally, differences in amount and type if melanin causes variation in skin color

Question 28

Characteristics of skin color

Answer 28

Melanin is primary pigment Skin colors track geography Dark skin provides protection against UV radiation near equator Lighter skin evolved away from the equator (UV rays promote vitamin D synthesis for calcium absorption)

Question 29

Characteristics of carotene

Answer 29

Yellow-orange pigment Obtained in diet, too much can cause skin to turn orange (carotenemia) Accumulate in stratum corneum

Question 30

Characteristics of hemoglobin in skin color

Answer 30

Protein in red blood cells Causes reddish hue in light color skin with little melanin

Question 31

Sun tanning and burns

Answer 31

Skin darkens with exposure to UV radiation for protection Melanocytes respond to UV radiation by increasing production of melanin Too much UV radiation = sun burn (damage to epidermis resulting in inflammatory response: redness, swelling, pain)

Question 32

Characteristics of subcutaneous tissue

Answer 32

Deep to the dermis, not part of the skin Called the hypodermis or superficial fascia Composed of loose areolar connective tissue and adipose connective tissue

Question 33

Functions of subcutaneous tissue

Answer 33

Fat storage Insulation Anchor skin to underlying structures with moveability

Question 34

What are skin appendages

Answer 34

Derivatives of the epidermis but extend into dermis Fingernails, hair, sebaceous glands, sweat glands

Question 35

Characteristics of fingernails

Answer 35

Composed of dead, keratinized cells (similar to hoofs or claws) Nail plate with a foot embedded in skin Proximal end (nail matrix) continuously growing part of nail

Question 36

Characteristics of hair

Answer 36

For protection and touch sensation Long keratinized filaments with pigment from melanocytes of hair follicle (graying due to decreased melanin production)

Question 37

Hair types

Answer 37

Vellum hair: fine, short hairs all over body Terminal hair: long, thicker hair (scalp, armpits, pubic region)

Question 38

Characteristics of hair follicles

Answer 38

Tubular invagination of epidermis from which hair grows Extends down into dermis Bulb wrapped by nerve endings- great touch receptors Arrector pili (smooth muscle in dermis) attach to hair follicle and erect hair with goosebumps

Question 39

Characteristics of sebaceous glands

Answer 39

Oil glands of skin (produce sebum) Cover entire body except palms and soles Associated with hair follicles

Question 40

Functions of sebaceous glands

Answer 40

Softens, lubricates skin and hair Collects dirt and kills bacteria Slow water loss

Question 41

Types of sweat glands

Answer 41

Eccrine glands, apocrine glands, ceruminous glands, mammary glands

Question 42

Characteristics of eccrine glands

Answer 42

More numerous, many on palms, soles, and forehead Glands in dermis of skin Sweat released through pores in epidermis Helps with temperature regulation

Question 43

Characteristics of apocrine glands

Answer 43

Found in armpit, anal, and genital areas Ducts open into hair follicles Secretions considered pheromones, involved with sexual signaling Start function at puberty

Question 44

Characteristics of ceruminous glands

Answer 44

Line external ear canal Produce wax (cerumen) in the ear canal

Question 45

Characteristics of mammary glands

Answer 45

Modified to secrete milk Part of integumentary system but important part of female reproduction