Integumentary

Question 1

skin

• layers
• general composition of each layer

Answer 1

epidermis
-epithelial layer (ectoderm)
dermis
-connective tissue (mesoderm)

Question 2

dermis

-interdigitation properties

Answer 2

dermal papillae
-projections of dermis into epidermal base
epidermal ridges
-adjoining epidermal projections that correspond to dermis surface

Question 3

interdigitations

• purpose
• take what type of configurations in thin vs. thick skin

Answer 3

purpose
-provide structural and morphological integrity between epidermis and dermis (in addition to cellular connections)
configuration in thin skin
-peg and socket
thick skin
-ridges and grooves

Question 4

hypodermis

• location
• type of tissue
• contains
• how does it connect to skin?
• underlying tissue covered by…

Answer 4

location
-deep to dermis
tissue type
-subcutaneous loose connective tissue
contains adipocytes (fat cells)
not part of skin, but forms loose adhesion of skin to underlying tissue
underlying tissue covered by a fascia plane, which has a variable appearance

Question 5

skin functions (4)

Answer 5

receptor organ
protection against impact and friction
protection against UV - pigment melanin
thermoregulation, body metabolism and excretion via glands, blood vessels, and adipose

Question 6

epidermis

• type of tissues
• contains

Answer 6

type
-stratified squamous keratinized epithelium (named for most superficial strata of epidermis)
contains
-keratinocytes - keratinizing epidermal cells
-melanocytes
-langerhans cells - immune system
-merkel cells - sensory receptors?

Question 7

skin thickness

• epidermis
• dermis + epidermis

Answer 7

epidermis
-75-150 um (micrometers) vs. 400-600 um
--no explanation of comparison in notes (different areas of the body?)
total
-up to 4 mm

Question 8

types of skin

-characteristics

Answer 8

thick (glabrous)
-smooth, non-hairy
-some books use stratum lucidum as a marker for this type of skin
thin
-hairy

Question 9

keratin producing cells (keratinocytes) in epidermis

-names of the layers (5)

Answer 9

stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum

Question 10

stratum basale

• superficial or deep?
• it is basophilic - explain
• single cell layer rests on…
• purpose of desmosomes and hemidesmosomes
• produce filaments called…
• highly mitotic - why?

Answer 10

deepest layer
basophilic
-abundant in rough ER (endoplasmic reticulum)
-these produce protein
single cell layer rests on basal lamina
desmosomes and hemidesmosomes attach stratum basale to underlying layer
produce filaments called cytokeratins
high mitotic
-partly responsible for constant renewal of overlying layers

Question 11

stratum spinosum
-how many layers
-cell shapes
-mitotic or not
-tonofibrils
where is this layer thicker?

Answer 11

more than 1 layer
shapes
-variety: cuboidal, polygonal, “slightly” squamous
mitotic
tonofibrils
-tonofilament bundles that attach to the desmosomes interconnecting each cell
-give the spinous appearance in histological preparations
thicker in areas of greater abrasion

Question 12

stratum granulosum

• how many layers
• what shape are the cells?
• stains dark due to…
• purpose
• -what structures are responsible for this process?

Answer 12

3-5 layers
polygonal cells
stains dark due to...
-keratohyalin granules
purpose
-acts as extracellular cement
-purpose achieved due to lamellar granules
--lipid-rich product secreted by these cells to "seal" the skin

Question 13

stratum lucidum

• more apparent in…
• appearance
• type of cell
• lacks what function…
• what structures are missing?
• densely packed with…
• what holds the cells together?

Answer 13

more apparent in thick skin
appearance
-extremely flattened
type of cell
-eosoniphilic
lacks protein synthesis
organelles and nuclei are gone
densely packed with cytokeratin filaments embedded in matrix
desmosomes present to hold cells together

Question 14

stratum corneum

• appearance
• is there a nucleus?
• thickness
• filled with…
• -this is embedded in

Answer 14

flattened cells
no nuclei
15-20 layers thick
filled with protein keratin
keratin is embedded in matrix from keratohyalin granules (from stratum granulosum)

Question 15

other cells found in epidermal layers

• names
• primarily found in which layers?

Answer 15

melanocytes
langerhans cells
merkel’s cells
primarily found in stratum basale and spinosum (2 deepest layers)

Question 16

melanocytes

• origin
• location
• function

Answer 16

neural crest in origin
found in and beneath stratum basale
produce melanin

Question 17

melanin

• purpose
• how do they accomplish this purpose?
• how does it get moved through the skin?

Answer 17

purpose
-encircle the nucleus of the keratinocytes to protect their genetic material from UV radiation
movement
-melanin is packaged into vesicles (through a series of changes that darken and condense) and then extruded and picked up by cells of the malpighian layer

Question 18

sun tan

-what does it do to melanin

Answer 18

increases the “darkening” of melanin

speeds up release into the malpighian layer

Question 19

what is the malpighian layer?

Answer 19

Wikipedia - both the stratum basale and stratum spinosum

Question 20

langerhans cells

• what are they?
• purpose

Answer 20

bone marrow derived macrophages (mesoderm)
purpose
-bind antigens (function with immume system)

Question 21

Merkel’s cells

• location
• purpose

Answer 21

within thick skin
purpose
-may be sensory due to association with free nerve endings

Question 22

where are the majority of sensory nerve endings in the skin?

Answer 22

dermal layer

Question 23

dermis

• type of tissue
• layers
• -characteristics of each layer

Answer 23

tissue type
-connective
-dense irregular
papillary layer
-dermal pegs
-lamina reticularis: reticular fibers that contribute to basement membrane
reticular layer
-dermatan sulfate elastic fiber newtork

Question 24

dermis

• characteristics
• location of blood supply

Answer 24

encapsulated nerve endings
epithelial invaginations
rich blood supply
-deep to epidermis-dermis interdigitation

Question 25

examples of epithelial invaginations

Answer 25

hair sweat glands sebaceous (oil-producing) glands

Question 26

sebaceous glands - type - location - function - when do they begin to function? - associated pathology

Answer 26

``` type -acinar (alveolar) glands location -ducted into hair follicle function -produce sebum begin to function at puberty pathology -acne if plugged ```

Question 27

sebum - what is it - how is it secreted?

Answer 27

fat of the gland and remnant of dead secretory cells secretion -holocrine secretion (whole cell is secreted)

Question 28

sweat glands | -types

Answer 28

eccrine | apocrine

Question 29

eccrine - another name - location - appearance - function

Answer 29

``` also called merocrine location -open to skin surface appearance -simple coiled tubular glands watery secretion produced in response to changes in body temperature ```

Question 30

apocrine - size compared to eccrine glands - location - open to... - responsible for... why?

Answer 30

larger than eccrine can extend to hypodermis from skin surface open to hair follicles responsible for body odor -secretion is viscous and allows for bacterial decomposition, which leads to odor

Question 31

hypodermis - tissue type - location - function - what accumulates there?

Answer 31

``` type -subcutaneous -loose connective tissue beneath the dermis loosely binds skin to underlying musculoskeletal system adipocytes accumulate there ```

Question 32

types of carcinomas

Answer 32

actinic keratosis squamous cell carcinoma basal cell carcinoma malignant melanoma

Question 33

actinic keratosis - what is it? - can turn into... - also knows as... - -why

Answer 33

precancerous changes to corneal (most superficial) layer of epidermis may turn into squamous cell carcinoma also known as Solar keratoses because of... -prevalence on exposed skin surfaces - arms, face, scalp (in those w/out a nice coif of hair

Question 34

squamous cell carcinoma | -danger level

Answer 34

locally invasive | can metastasize

Question 35

basal cell carcinoma - how common is it? - how destructive?

Answer 35

most common type of epidermal cancer | destructive to local tissue

Question 36

malignant melanoma | -why is it malignant?

Answer 36

malignant because melanocytes migrate into the epidermal layers as a result, they will readily leave the local tissue and travel throughout the body and invade all tissues and organs this makes them a highly metastatic type of cancer

Question 37

wound healing - what predicts the type of epithelial and connective tissue response? - stages of cutaneous wound healing

Answer 37

``` thickness of wound predicts response stages -immediate or hemostasis -inflammation -proliferation -maturation ```