A&p.integumentary.2

Front 1

what does the epidermis consist of?

Back 1

keratinized stratified squamous epithelium

Front 2

is the epidermis vascular or avascular?

Back 2

avascular; therefore, it relies on nutrients and oxygen from diffusion from capillaries within the dermis

Front 3

where are the cells in the epidermis with the highest metabolic demand?

Back 3

closest to the dermis because the epidermis is avascular

Front 4

what are the 4 types of cells of the epidermis?

Back 4

1. keratinocytes
2. melanocytes
3. langerhans (dendritic)
4. merkel cells

Front 5

which cell type dominates the epidermis?

Back 5

keratinocytes

Front 6

what are keratinocytes?

Back 6

they're the most abundant cell in the epidermis
- form several layers (strata)
- continuously produced by stem cell division in deepest layers
- shed at the exposed surface

Front 7

how are keratinocytes produced?

Back 7

by stem cell divisions in deepest layers

Front 8

what are melanocytes?

Back 8

they produce melanin- involved in skin coloration
- located in stratum basale
- protect against UV radiation because the melanosomes are concentrated around the nucleus

Front 9

what two substances are involved in skin coloration?

Back 9

melanin and carotene

Front 10

what are langerhans cells?

Back 10

also called dendritic cells
- they participate in the immune response by stimulating a defense

Front 11

what do langerhan cells create a defense against?

Back 11

- microorganism that manage to penetrate the superficial layers of the epidermis
- superficial skin cancers

Front 12

what are merkel cells?

Back 12

-sensitive to touch due to tactile discs
-release chemicals that stimulate sensory nerve endings
-scattered among the basal cells

Front 13

what are the 5 epidermal layers from deepest to superficial?

Back 13

1. stratum basal
2. stratum spinosum
3. stratum granulosum
4. stratum lucidum
5. stratum corneum

Front 14

what is the stratum basale?

Back 14

-its the deepest layer
-consists of single row cuboidal or columnar keratinocytes
-stem cells- basal cells- dominate this layer
-keratinocyte cytoskeleton
- melanocytes and merkel cells are scattered among the basal cells

Front 15

what are basal cells?

Back 15

they dominate the stratum basale; they are stem cells whose divisions replace the more superficial keratinocytes that are lost or shed at the epithelial surface

Front 16

what is the keratinocyte cytoskeleton?

Back 16

-tinofilaments: keratin
-attachment to desmosomes; hemidesmosomes- attach the cells of this layer (stratum basale) to the basal lamina

Front 17

what is the stratum spinosum?

Back 17

-8-10 layers of multiple-sided keratinocytes bound together by desmosomes
-include dendritic cells, langerhans cells, and melanocytes
-tonofilaments: desmosomes that bind the layers of keratinocytes

Front 18

what are dendritic cells?

Back 18

stimulate defense against microorganisms and superficial skin cancers

Front 19

what is the stratum granulosum?

Back 19

-3-5 layers of flattened keratinocytes
- its the transition layer between metabolically active strata and dead cells

Front 20

what do the layers in the stratum granulosum consist of?

Back 20

-apoptosis
-keratohyalin
-lamellar granules

Front 21

what happens once the cells reach the stratum granulosum?

Back 21

by the time the cells have reached this layer most have stopped dividing and started making large amounts of keratin and keratohyalin

Front 22

what is the stratum lucidum?

Back 22

-it separates the stratum corneum from deeper layers
-its only in the think skin
-3-5 layers flattened and clear filled with dead keratinocytes

Front 23

why are the keratinocytes in the stratum lucidum dead?

Back 23

because they're undergoing dehydration causing thickened plasma membranes; keratin

Front 24

what is the stratum corneum?

Back 24

-25-30 layers flattened, filled with dead keratinocytes that are tightly interconnected by desmosomes
- they continuously shed
-cell interior is mostly keratin; interstitial lipids
-callus

Front 25

what does the dermis consist of?

Back 25

-a papillary layer of areolar tissue and a reticular layer of dense irregular CT
-blood vessels, nerves, glands, and hair follicles

Front 26

explain the CT in the dermis:

Back 26

strong connective tissue consisting of collagen and elastic fibers; includes fibroblasts, macrophages, and adipocytes

Front 27

what is the papillary region of the dermis?

Back 27

-consists of areolar CT
-nourishes and supports the epidermis
-includes dermal papillae

Front 28

what is the dermal papillae?

Back 28

-in the papillary region, consists of capillary loops, meissner corpuscles, free nerve endings, epidermal ridges, and is sensitive to light touch

Front 29

what is the reticular region of the dermis?

Back 29

-consists of dense irregular CT
-restricts spread of pathogens, stores lipid reserves, attaches skin to deeper tissues, thermoregulations due to blood vessels
-adipose cells, hair follicles, nerves, sebaceous glands, sudoriferous glands, sensitive to deep pressure and vibration

Front 30

what are the three accessory structures of the skin?

Back 30

1. hair
2. exocrine glands
3. nails

Front 31

what is hair?

Back 31

produce hairs that protect the skull and provide delicate touch sensations on general body surface

Front 32

what are exocrine glands?

Back 32

assist in thermoregulation, excrete wastes, and lubricate epidermis

Front 33

what are the three types of exocrine glands?

Back 33

1. sebaceous glands
2. sudoriferous glands
3. ceruminous glands

Front 34

what are sebaceous glands?

Back 34

oil glands that discharge oily lipid secretion called sebum that coats the hair shaft and surrounding epidermal surfaces

Front 35

what are sudoriferous glands and the two types?

Back 35

sweat glands
1. apocrine
2. merocrine

Front 36

what are apocrine sweat glands?

Back 36

founds in armpits, around nipples, and pubic region; produce sticky, cloudly, and sometimes odorous secretion

Front 37

what are merocrine sweat glands?

Back 37

they discharge secretions onto surface of the skin

Front 38

what do nails do?

Back 38

they support and protect tops of fingers and toes

Front 39

what is thermoregulation?

Back 39

maintenance of normal body temp through either insulation or evaporate cooling

Front 40

what are the seven main functions of integument?

Back 40

1. thermoregulation
2. blood reservoir
3. protection
4. cutaneous sensations
5. excretion
6. ansorption
7. synthesis of vitamin D

Front 41

what are cutaneous sensations?

Back 41

detection of touch, pressure, pain, and temperature stimuli, and the relaying of that information to the nervous system