epidermis

Question 1

integumentary system structures

Answer 1

1. skin (subcutaneous membrane)
2. accessory structures:
   -hair
   -nails
   -exocrine glands
   -sebaceous
   -sweat

Question 2

integumentary system functions

Answer 2

1. protection: of underlying tissues and organs- uv light, microorganisms, water loss
2. sense: touch, pressure, pain, temp
3. temp regulation: blood flow through skin; sweat glands
4. vitamin D3 production
5. excretion: salts, water, waste

Question 3

skin layers

Answer 3

1. epidermis
2. dermis
3. hypodermis

Question 4

epidermis

Answer 4

1. outermost layer
2. KERATINIZED, stratified squamous
   -cells arranged into layers or STRATA
3. avascular
   -nourished from capillaries in
   papillary layer
4. BASEMENT MEMBRANE separates from dermis
   
   • living/actively dividing cells
   • push older cells to surface as new
     are produced

Question 5

keratin

Answer 5

intracellular fibrous protein
-gives hair, nails, and skin their hardness and water resistant properties

Question 6

kerainization

Answer 6

as cells move outward through layers they fill with keratin and die
-serves as a layer that resists abrasion and gives permeability
-eventually dead cells will desquamate or slough off

Question 7

types of cells in epidermis

Answer 7

1. keratinocytes
2. melanocytes
3. dendtritic (langerhans) cells
4. Merkel cells

Question 8

keratinocytes

Answer 8

cells in al layers except stratum basale
-produce keratin for strength

Question 9

melanocytes

Answer 9

reason for hair and skin color
-melanin is transferred to keratinocytes
-same # of melanocytes in everyone

Question 10

dendritic (langerhans) cells

Answer 10

part of immune system

Question 11

merkel cells

Answer 11

light touch/superficial pressure

Question 12

layers of epidermis

Answer 12

(deepest to superficial)
1. stratum basale: high mitotic activity
2. stratum spinosum: limited cell division of keratinocytes; contains dendritic cells
3. stratum granulosum: flattened cells; keratin granules in cytoplasm
4. stratum lucidum; thin, clear zone- PALMS AND SOLES ONLY
5. stratum corneum- cornified cells (flattened dead cells filled with keratin) desquamation

Question 13

thick skin

Answer 13

a. all 5 epithelial strata
b. found in palms, fingertips, soles
c. fingerprints/footprints
-come from dermal papillae
d. no hair growth

Question 14

thin skin

Answer 14

a. no stratum lucidum
b. more flexible
c. covers rest of body
d. hair growth

Question 15

skin color PIGMENTS

Answer 15

a. melanin: protect from UV light. brown, black, yellow, or red
-melanocytes: mostly in stratum basale; extend between keratinocytes
-production determined by genetics, hormones, exposer to sun

b. carotene: yellow pigment
-accumulates in corneum, adipose cells, and hypodermis

Question 16

skin color BLOOD CIRCULATION

Answer 16

a. reddish hue (blushing, anger, inflammation)

b. cyanosis: blue color caused by decrease in blood oxygen

Question 17

skin color THICKNESS OF STRATUM

Answer 17

thicker areas can be yellowish