EXAM2_L16_17_Integument Flashcards
What are the 5 derivatives of Epidermis? Where derived from?
Surface Ectoderm
- Hair follicles,
- Sebaceous glands
- Sweat (sudoriferous) glands
- Nails
- mammary glands
What is hypodermis? is it part of integument?
Subcutaneous fascia- not part of integument
Integument is EPIDERMIS and DERMIS
Integument- 2 parts and defining layers
Epidermis- above papillary layer (BSGLC)
Dermis- between subcutaneous & Epidermis
-Contains reticular layer (glands/ducts/vessels)
and papillary layer
What type of epithelium for Epidermis and dermis?
Epidermis- keratinized stratified squamous ECs
Dermis- LCT, DiRCT
Dermal papillae vs epidermal rete ridges
Dermal papillae- dermis ridges protruding into epidermis
epidermal rete ridges- epidermis protruding into dermis
5 Layers of integument? What cells in each layer?
- Basale
- Spinosum (melanocytes, dendritic cells, keratinocyte)
- Granulosum
- Lucidum
- Corneum
Basale- Name- Structure- 3 Function- dysfunction?
germinativum
-single cell layer-cuboidal/low columnar/
-vitD production-Stemcells- desmosomes/hemidesmosomes
PSORIASIS- rapid proliferation of cells ~7days vs 50
Spinosum
Prickle cell layer
cuboidal to squamous
-vitD- mitotically inactive-cytoplasmic spines-
DESMOSOMES-(NODES OF BIZZOZERO)
Granulosum- thickness? observation? important structural component?
1-3 layers- squamous cell
Still retain nuclei
Keratohyalin granules (keratinization)
Corneum
squamous- variable thickness no nucleus keratinized cells (soft keratin)
Papillary Layer- composition? Where at?
Dermis- between basale and reticular layer
-LCT (more cellular than reticular layer)
-thin collagen fibers I and III
Thin elastic fibers
Reticular Layer- Composition? Where at?
Dermis- under papillary layer
- DiRCT- Thick Collagen Type I fibers- Thick Elastic Fibers
- Less cellular
- closely packed fiber bundles
EVG Stain- what highlighted? Color?
Weigert elastic stain?
Collagen fibers- Red
Elastic fibers- Black
WES-Highlights elastic and collagen fibers
Langer’s Lines
collagen & elastic fibers orient in parallel lines
surgeons use these lines for faster wound healing
Wound healing- 4 things
Stratum basale ramps up mitosis
- -migration of proliferating cells
- -exfoliation of dead keratinocytes frees scab
- -fibroblasts differentiate into myofibroblasts (directed by TGF-B1)
- -Myofibroblasts involved in wound closure
2 functions of Keratinocytes?
Where are they located and why?
-Flaggrin & Int. Filaments (keratin filaments-tonofilaments)
1. KG’s aggregate tonofilaments into tonofibrils by releasing Flaggrin
2. Water barrier-Lamellar bodies exocytosis pro-barrier lipids,enzymes,proteases into ICS between granulosum/corneum
Keratinocytes located at Basale b/c bound by hemidesmosomes
Nodes of Bizzozero
Desmosomes connecting cytoplasm of keratinocytes
called Bizzozero AT LM
Desquamation
Exfoliation-
-result of proteolytic degradation of desmosomes in a pH dependent manner
Melanocytes- Derived from? Migrate from?to? What drives? What function? what don’t they have? transport?
REMEMBER THEY LOOK LIKE AN UPSIDE DOWN ORANGE OCTOPUS IN THE PICTURE
- Neural Crest
- migrate to stratum basale
- PAX3 of dermis drives differentiation
- No desmosomes
- Produces melanin granules
- Transport kinesin/dynein
How do MELANIN granules end up in keratinocytes? what determines integument pigmentation?
- keratinocytes phagocytose melanocyte processes to take up melanin granules
- Pigmentation determined by rate of melanin degredation
3 epidermal cancers. ABCD rule
What is happening to keratinocytes?
- Basal cell carcinoma
- Squamous cell
- malignant melanoma
ABCD: asymetrical shape, border irregular, color variation, diameter >6mm
Keratinocytes migrating into the Stratum Spinosum layer
Langerhan’s cells: Function? What kind of cell? where migrate from? 3 structural characteristics?
- Immunocytochemistry CD1a
- APC’s (present to T-lymphocytes)
- migrate from marrow to spinosum
1. indented nucleus-
2. no desmosomes-migratory
3. rod-shaped BIRBECK GRANULES in cytoplasm
Langerhans cells- Lectin Langerin- Birbeck granules-HIV-1
WHAT IS THIS SHIZ?
Langerhans cells express lectin Langerin
- induces formation of Birbeck granules
- BG’s internalize and degrade HIV-1
Merkel’s Cells- Where derived?- Found in what layer? in what part of body? 2 Structure details? 2 Functional details? What stain used?
Merkel cell carcinoma- rare but agressive- Sun exposure like BCC
Ectoderm derived -in stratum basale -in fingertips -dense-cored neurosecretory granules -desmosomes tether MC's to keratinocytes -synapse w/ pseudounipolar neurons -tactile sensation Toluidine blue stain- appear lighter in color/large round nucleus