1
Q
A
2
Q
type of epithelium of the epidermis?
A
keratinized stratified squamous cell
3
Q
cells found in epidermis
A
melanocytes, merkel cells, langerhans cells, keratinocytes, corneocytes
4
Q
melanocytes?
A
create melanin to protect skin from UV damage
5
Q
merkel cells
A
tactile cells for fine touch
6
Q
langerhans cells?
A
immune surveillance and antigen presenting cells
7
Q
keratinocytes make up how much of epidermis
A
90%
8
Q
corneocytes?
A
dead keratinocytes on the outside
9
Q
what is present between corneocytes?
A
lamellar membranes
10
Q
melanocytes are found in
A
basale layer
11
Q
are melanocytes anchored?
A
NO; not anchored due to dendritic processes to kertinocytes
12
Q
melanocytes have desmosomes or hemidesmosomes?
A
might have hemidesmosomes attached to the basement membrane
13
Q
merkel cells are found in
A
tylotrich pads in basale layer
14
Q
tylotrich pads?
A
thickened areas of epidermis
15
Q
merkel cells form …
A
merkel discs when combined with sensory afferent nerve fibers
16
Q
are merkel cells anchored?
A
YES; they have desmosomes!!
17
Q
function of merkel discs
A
transmits the touch signal to CNS
18
Q
langerhans cells are found in
A
stratum spinosum
19
Q
are langerhans cells anchored?
A
NO; not anchored
20
Q
ID from left to right
these are the cells of epidermis
A
keratinocytes
lipids
corneocytes
21
Q
layers of epidermis
from superficial layer to deepest
A
stratum corneum
stratum lucidum (thick skin only)
stratum granulosum
stratum spinosum
stratum basale
22
Q
stratum corneum?
A
non-viable portions of epidermis where corneocytes reside
23
Q
stratum lucidum?
A
think lucent layer in thick skin only
24
Q
stratum granulosum?
A
produce lipid and contain keratohyalin granules
25
keratohyalin granules are seen how in histology?
purple granules in stratum granulosum
26
stratum spinosum?
has spiny processes due to desmosomes
proliferates keratin 1 and 10 and downregulate keratin 5 and 14
27
keratin 1 and 10 ?
are very hardy → help with mechanical stress in stratum spinosum
28
stratum basale?
bottom layer that touches the dermis where division occurs
29
why basal cells are germinative cells?
they actively divide to regenerate epidermis
daughter cells are pushed up
30
basal keratinocytes express which keratins?
keratins 5 and 14
31
T/F
keratins are intermediate filament proteins?
TRUE
32
keratin 5 and keratin 14 form ..
heterodimers that connect to hemidesmosomes
33
ID from the top to bottom
stratum corneum
stratum lucidum
stratum granulosome
stratum spinosum
stratum basale
34
ID from the top to bottom
stratum corneum
stratum grannulosome
stratum spinosum
stratum basale
35
cornification starts with a ...
dead cell with all of its organelles degraded
36
four things happening during cornification
1. keratin fibers condensed down to from corneocyte core
2. transglutamination to make cornified envelope
3. formation of lipid lamellar bilayers
4. desquamation
37
how is corneocye core formed?
1. keratohyalin granules release filaggrins
2. filaggrins bind to keratin fibers → condense them down into a clump
38
how is the corneocyte envelope formed?
1. keratohyalin releases proteins and filaggrins
2. transglutamases cross-link those proteins to make the envelope
39
transglutamination?
cross-linking proteins released by keratohyalin to form cornified envelope
40
cornified envelope?
tough, protein-lipid bilayer that replaces the plasma membrane in corneocytes
41
what are some proteins that are cross-linked by transglutamses?
filagrins, loricrins, involucarins ...
42
transglutamination is activated by
calcium
43
after cornified core and envelope are produced, filagrins are...
broken down into free amino acids = natural moisturizing factors
44
function of cornified envelope
mechanical strength
resistance to water loss
45
where is lamellar body produced?
golgi in keratinocytes in granulosome
46
lamellar bodies?
contain lipid and desquamating enzymes
47
how is the lipid lamellar bilayer produced?
1. lamellar bodies fuse with the plasma membrane
2. release its content out of the cell
3. released lipids will fit themselves in the cornified envelope
48
function of lipid layers between corneocytes
prevent transepidermal water loss
49
desquamation?
desquamating enzymes cause outer layer of corneocytes to shed
50
degradation of organelles before cornification happens where?
when moving from granulosum to corneum
51
two types of intercellular junctions
desmosomes and hemidesmosomes
52
desmosomes?
connect cell to cell
53
two transmembrane proteins of desmosomes?
desmocollin-1 and desmoglein-3
54
desmosome proteins are found between
keratinocytes
55
desmocollin-1 affects ..
skin only
56
desmocollin-1 is highly concentrated in
superficial surface
57
desmogleins-3 is highly concentrated in..
stratum basale
58
desmoglein-3 affects
skin AND mucous membranes
59
hemidesmosomes?
connect cell to basement membrane
60
where is basement membrane?
between epidermis and dermis
61
two proteins of hemidesmosomes?
integrins and plectins
62
integrins?
transmembrane proteins that anchor to the basement membranes
63
plectins?
cytoplasmic linker proteins that bind to keratins
64
T/F
plectins are located inside the hemidesmosomes
TRUE
65
what are those purple boxes?
desmosomes
66
what are those yellow boxes?
hemidesmosomes
67
T/F
basement membranes are present in all tissues
TRUE
68
four layers of basement membranes from superficial to deepest
1. plasma membranes (where hemidesmosomes are located)
2. lamina lucida
3. lamina densa
4. lamina reticularis
69
lamina reticularis AKA
sublamina densa
70
what is found in lamina lucida?
laminins
71
what's found in lamina densa?
collagen type 4
72
what's found in lamina reticularis?
collagen type 7 and 3
73
basal lamina?
lamina lucida + lamina densa
74
when seen under electron microscopy, how does lamina lucida look like?
electron lucent, lighter staining
75
when seen under electron microscopy, how does lamina densa look like?
electron dense, darker staining
76
collagen type 4?
sheet-like with a lot of carb chains
77
collagen type 4 can be labeled with
PAS
78
basement membrane is rich in ...
glycoproteins
79
What layer of BMZ is Collagen VII within?
lamina reticularis
80
What layer of BMZ is Collagen IV within?
lamina densa
81
What layer of BMZ is laminins within?
lamina lucida
82
What structure normally keeps keratinocytes attached to
one another?
desmosomes
83
This is an autoimmune disease affecting only the more
superficial layers of the epidermis of the haired skin of this
dog (no mucous membranes effected). Which adhesion
protein is likely being targeted?
Desmocollin-1 (DSC-1)
84
the dogs haired skin and mucous membranes
were affected. Remember that one of the clinical
differentials was a suprabasilar (just above the basal cell
layer) clefting disorder. Which adhesion protein would
likely be affected for that differential?
Desmoglein-3
(DSG-3)
85
which process has dysfunction when you notice:
- hyperkeratosis
- cell lysis within the more superficial viable keratinocyte layers
-large, irregular keratohyalin grannules
cornification
86
Mitotically active layer of the epidermis?
stratum basal
87
Keratins expressed in basal layer
keratins 5 and 14
88
Spiny layer of epidermis
stratum spinosum
89
Consists of mixture of proteins, including
profilaggrin (precursor to filaggrin), which
contributes to aggregation of keratin
filament bundles.
Keratohyalin granules
90
Stores and secretes lipids to the
extracellular space of stratum corneum,
which is important for prevention of
transepidermal water loss
lamellar bodies
91
Calcium dependent enzymes involved in
formation of cornified envelop through
crosslinking of proteins, such as loricrin and
involucrin
transglutaminases
92
Flattened, anucleate, nonviable
keratinocyte
corneocytes
93
Degrade corneodesmosomes and thus
critical in detachment and shedding of
nonviable skin cells
proteases (desquamating enzymes)
94
basal keratinocytes have more basophilic or eosinophilic cytoplasm?
basophilic
95
keratinocytes in which layer contain keratohyalin granules?
stratum granulosum
96
T/F profilaggrins are cysteine and histidine rich
TRUe
97
corneocytes contain
- keratin filaments
- lost their nucleus and organelles
- a plasma membrane that is coated with an lipid
98
stratum corneum is thickest in
areas subject to lots of friction
99
lamellar bodies secrete lipids at where?
the junction of the stratum granulosum and stratum corneum
100
lamellar bilayers in the corneum have a mixture of ...
cholesterol, fatty acids, ceramides
101
cornedesmosomes?
intercorneocyte adhesions
102
do desmodomes contain keratin intermediate filament
yes
103
basement membrane can be visualized by which special staining?
PAS; they appear as pink band
104
collagen 7 has binding sites for what?
collagen 4 and laminins in the lamina densa
105
collagen 7 is found in sublamina densa and connects to
connects to collagen 3 in papillary dermis
106
collagen 7 associate with collagen 3 in where?
sublamina densa
107
VM 519
flashcards
Decks in class (17)
# Cards
-
Intro to skin78
-
Connective and Epithelial Tissues106
-
Dermis and Subcutis87
-
Epidermis107
-
Topicals51
-
histology21
-
Wound Healing74
-
Microbiome41
-
Melanocyte Migration40
-
Microbes39
-
Equine Hoof Histology and Nail Microanatomy25
-
Antibiotics75
-
Glands62
-
Hair Follicles61
-
External Ear Canal and Middle Ear25
-
Eyelids, Conjunctiva, and the Tear Film28
-
Skin Cytology30
