general - anatomy of the skin

Question 1

3 parts of the skin

Answer 1

epidermis
dermis
hypodermis

Question 2

function of epidermis

Answer 2

physicall barrier

• prevent water loss
• prevent pathogen entry

Question 3

type of epithelium in the epidermis

Answer 3

stratified squamous epithelium

Question 4

what is turnover time

Answer 4

life span of daughter epidermal cells from their production to their exfoliation from the skin

Question 5

how long is the turnover time in normal skin

Answer 5

28 days

Question 6

4 types of cells in the epidermia

Answer 6

keratinocytes
- accumulatte keratin as they move upwards and mature
melanocytes
-transfer melanin to keratinocytes 
langerhans cells
-immune cells that recognie allergens 
merkel cells 
-nobody knows

Question 7

4 layers of epidermis

Answer 7

stratum basale
statum spinosum
stratum granulosum
stratum lucidum

Question 8

anatomy of the basement membrane

Answer 8

• consits of 2 layers
  1) bassal lamina
  2) reticular connective tissue

basal lamina is further divided into 2 parts

1) lamina lucida
- clear layer consisting of (LIED)
- laminin , integrins, entactins, dystroglycans
- type 7 collagen cells
2) lamina densa
- closer to connective tissue (dermis)
- consits of reticlar collagen 4 fibers

Question 9

function of basment membrane

Answer 9

• anchors epithelium to dermis using substrate adhesion molecules (SAMS)
• mechanical barrier against malignant cells invasions leading to CIS
• angiogenesis

Question 10

stratum basale anatomy

Answer 10

thin unicellular layer of basal cells in contact w/ basement membrane

Question 11

describe cells of statum basale

Answer 11

• basophilic cytoplasm
• eliptical nucleus w/ chromatin
• desmosomes for cellular attatchment
• gapjunctions for cellular communication
• hemidesmosomes for ancoring and comm w/ basement membrane

Question 12

stratum spinosum anatomy

Answer 12

multicellular layer (5)
cells connected by desmosomes 
suprabasal cells have spinelike processes 
larger than basal cells 
spinelike nuclei

Question 13

stratum granulosum

Answer 13

3 or so cell layers

cells contain BASOPHILIC KERATOHYALINE GRANULES

Question 14

stratum lucidum

Answer 14

thin layer found in ther epidermis of lips, palms and soles

Question 15

stratum corneum

Answer 15

multicellular (10)
consists of dead keratinised cells
layers have sequencial exfoliation
horny cells flat w/ keratin fibers

Question 16

alternartive name for basophilic keratohyaline granules

Answer 16

odham bodie

keratosome

Question 17

what is the keratin pattern

Answer 17

contrast seen in electron microscopy between the interfibrous substance(electon dense) and keratin fibers(less dense)

Question 18

how permeable is the basment membranw

Answer 18

semi permable

Question 19

where are hemidesmosomes located in the BM

Answer 19

on the dermal side

Question 20

where are pemphigoid antigens located

Answer 20

in lamina lucida

Question 21

how does the basal membrane appear on electron microscope

Answer 21

llamina lucida
- clear
lamina densa
-dense duh

Question 22

where are bullous acquisita antitgens located

Answer 22

lamina densa

Question 23

structures in the dermis (9)

Answer 23

collagen
elastic fibers
ground substance
fibroblasts
blood vessels 
lymphatics
nerves
errector pilli muscles 
immne cells

Question 24

dermal collagen structure and function

90% of dermal fibers

Answer 24

90% of dermal fibers

cross linked triple helix pptides
for tensile strength

papillary dermis-looseley arragend fibers

reticular dermis
- dense collagen fibers arranged in a parralel manner creating lines of tension called LANGER LINES

Question 25

what is the papillary dermis

Answer 25

upper most part in contact w/ the epidermis at ridges known as papilla

Question 26

reticular dermis

Answer 26

beneath papillary dermis
consists of desne reticular fibers that provide tesnile strength
hair, sebaceous glans, receptors, nails and blood vessels have hteir roots here

Question 27

what type of collagen stains silver

Answer 27

type 3 collagen around blood vessels

Question 28

collagen is synthesised by?

Answer 28

firbroblasts

Question 29

collagen is broken down by what enzyme

Answer 29

colllagenase

Question 30

what do fibroblasts make

Answer 30

collagen
elastic fibers
ground susbstance
fibronectin

Question 31

structure and function onf elastic fibers in dermis

Answer 31

10% of dermal fibers

restore skin to resting position after deformation (elastic)

Question 32

where are elastic fibers thickest

Answer 32

reticular dermis

Question 33

ground susbstance

Answer 33

an amorphous viscoelastic gel consisting of glycosaminoglycans made by fibroblasts

Question 34

function of ground subs

Answer 34

bonds water up to 1000 x its own weight

controls the flow of solues in and out of the dermis

Question 35

what degrades ground subs

Answer 35

mast cells

Question 36

where do fibroblasts orignate from

Answer 36

the mesenchyme

Question 37

where do the vessels in the dermis originate from

Answer 37

arteris in subcutaenous tissue (hypodermis)

Question 38

structure of dermal vessels

Answer 38

lined by endothelial cells and covered in collagen

vasodilation and constriction is controlled by the hypolamaus in response to

• heat/cold
• emotion

Question 39

errector pilli muscles structure and function

Answer 39

have their origin in BM
are smoothe muscles
cause piloerection in response to cold or fear

Question 40

most prominent areas of erector pilli

Answer 40

scrotum- tunica dartos

areola

Question 41

types of immune cells in dermis

Answer 41

lymph
neut
mono
mast

Question 42

what is the hypodermis

Answer 42

deepest part of skin consisting of subcutaneous fat

Question 43

function

Answer 43

store energy
insulation
shock absorbption
atrophies w/ age making us look older

Question 44

structure of adipose cells

Answer 44

lipocytes
group together to form lobules
blood vessels an verves surround them

Question 45

sites w/ most abount of subcutaneous fat

Answer 45

soles
palms
batty