U3 Summative - Integumentary System

Question 1

Skin Functions

Answer 1

• Makes skin tough (keratin)
• Barrier to penetration/injury
• Contains immune system cells (macrophages/langerhans cells: engulfs bacteria, found in the stratum spinosum)
• Regulates body temp. (maintains homeostasis)
• Houses sensory receptors
• Composed of several tissues
• Retards water loss (stratum corneum)
• Excretes small amounts of waste (sweat)
• Synthesizes chemicals

Question 2

Skin varies in thickness mostly due to:

Answer 2

variations in the stratum corneum (the uppermost layer)

Question 3

Epidermis

Answer 3

TOP LAYER - Stratified squamous epithelium, avascular, “cornified” with protein keratin, uses diffusion

Question 4

Layers of Skin

Answer 4

Epidermis
Dermis
Hypodermis

Question 5

Stratum Basale (Melanocytes, Merkel Cell/Disc, Cell Production)

Answer 5

Found in the basement membrane of the epidermis! Keratinocytes give rise to most new epidermal cells that are pushed outward during cell division, melanocytes (produce melanin), merkel cells/discs in conjunction with a dermal nerve ending, form a tactile/touch receptor

Question 6

Stratum Spinosum (Macrophages/Langerhans cells)

Answer 6

Macrophages (called Langerhans cells) are present in this layer and the stratum granulosum, mitosis happens here, several layers of flattened keratinocytes, comprised of filaments making the skin flexible/strong

Question 7

Statum Granulosum

Answer 7

This layer consists of two to five layers of cells with granules of keratohyalin (living cells); living keratinocytes creating keratin/adding keratin to new cells

Question 8

Stratum Lucidum

Answer 8

Clear & thin, only seen in thick skin such as the soles of the feet and palms

Question 9

Stratum Corneum

Answer 9

The stratum corneum is made up of 25-30 layers
of dead, keratinized cells.
A waterproof, protective outer layer.

Question 10

Dermis

Answer 10

Dermis: composed of fibroconnective tissue, with blood vessels, nerve endings,
sweat glands, hair follicles, and nail roots

Question 11

Papillary Dermis

Answer 11

Zone of areolar tissue (loose CT) closest to the epidermis, projecting upward as dermal papillae,
blood vessels extend close to the epidermis within the papillae,
the large number of white blood cells within this layer helps prevent infection

Question 12

Reticular Dermis

Answer 12

Dense irregular connective tissue, stretching of the skin causes tears in this area,
called linea albicantes, or stretch marks

Question 13

Hypodermis aka subcutaneous layer

Answer 13

Loose CT (adipose tissue), insulates, major BVs present, stores energy, fatty bottom layer

Question 14

Dermal Vitamin D Synthesis

Answer 14

1. UV radiation can penetrate into the dermis where it reaches 7-DEHYDROCHOLESTEROL found in blood/dermis
2. UV- rays convert it into CHOLECALCIFEROL
3. Kidneys/liver turn it into CALCITRIOL (active Vitamin D)

Question 15

Cutaneous Absorption

Answer 15

blood receives 1-2% of O2 through the skin, many compounds can be absorbed through the skin!

Question 16

Thermoregulation

Answer 16

dermail BVs contrict or dilate depending on temp. (sweat allows for evaporative cooling)

Question 17

Sensory Roles/Cutaneous Sensory Receptors/Corpuscles

Answer 17

Nerve endings, allows for sense and touch signals sent to the brain to be processed

Question 18

Hair (Pili)

Answer 18

• Made of hard keratin
• Accessory to the skin
• Growth of hair is due to mitosis in the cells in the stratum basale

Question 19

Lanugo

Answer 19

Covers the fetus before birth

Question 20

Vellus

Answer 20

Fine, unpigmented hair found all over the body

Question 21

Terminal hair

Answer 21

long, coarse, and pigemented; found on scalp, face (men), and axillary and pelvic regions after puberty

Question 22

Vibrissae

Answer 22

Short, “guard” hairs (found in nostrils)

Question 23

Arector pili muscle

Answer 23

Erects the hair follicles aka “goosebumps”

Question 24

Structure of nails

Answer 24

• Nail plate/protective, hard-keratin covering
  -Nail bed
• Lunula (above cuticle)
• Version of stratum corneum

Question 25

Sudoriferous Glands

Answer 25

the most numerous cutaneous (skin) glands. Sweat: mostly water; also, salts, ammonia, urea, sugar, uric acid, lactic acid, ascorbic and amino acids.

Question 26

Eccrine sweat glands

Answer 26

all over the body, produce watery perspiration to cool the body; ducts to skin surface, functional before and after puberty, sweat not very viscous

Question 27

Apocrine sweat glands

Answer 27

developed during puberty, odorous, found in the groin, axilla, breast areola

Question 28

Sebaceous glands

Answer 28

Everywhere minus the palms and soles; produces an oily sebum to moisturize skin and hair

Question 29

Ceruminous glands

Answer 29

Found in ears, earwax

Question 30

Breast/mammary sweat glands

Answer 30

Produces milk (for females)

Question 31

Burns

Answer 31

- First-degree burns involve only the epidermis - Second-degree burns involve the epidermis and upper dermis - Third-degree burns destroy the skin and deeper tissue (blackened)

Question 32

___% of your blood is in your skin?

Answer 32

5%

Question 33

How skin repairs itself:

Answer 33

Capillaries constrict to lessen bleeding, platlets plug the wound, inflammation, white blood cells clense the wound, fibroblasts build tissue, specialized fibroblasts close/constrict the wound, re-epithelialization

Question 34

The skin as we age:

Answer 34

- Scaly skin - Age spots - Dermis becomes reduced - Loss of fat - Wrinkles - Sagging - Sebaceous glands secrete less oil - Melanin production slows - Hair thins - Number of hair follicles decrease - Impaired nail growth - Sensory receptors decline - Inability to control body temperature - Less vitamin D production

Question 35

Keratinization

Answer 35

involves keratinocytes, process by which cells in the epidermis produce and accumulate to make the skin waterproof and durable (stratum corneum must be strong to prevent injury/penetration)