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
What 4 cells of epidermis?
- Keratinocytes (
- Melanocytes (Neural Crest)
- Langerhan’s (marrow->spinosum) APC’s
- Merkel’s (ectoderm)
Innervation of Integument 5 types. What structural characteristic of corpuscles?
- Free nerve endings (pain, temp, tactile)
- Pacinian corp. (deep pressure, vibration)-ret lam.
- Meissners corps (light touch. tactile)-derm pap.
- Merkel’s cells (tactile)
- Ruffini’s corps (tactile)
Corpuscles have CT encapsulated nerve endings
Hair Follicle 6 parts
Note: outside GM is dermis- inside is epithelium
- Hair (medulla/cortex/cuticle)
- IRS- int root sheath
- ERS-ext root sheath
- GM (glassy membrane=basal lamina)
- CT
- HP- hair papilla enclosed by hair bulb
Cortex, cuticle , hair cells (what type of cells in each)?
Cortex- cuboidal
cuticle - squamous cells
hair cells- hard keratin
color determined by melanin content and typej
Stroma & Parenchyma
Stroma- supporting cells
Parenchyma-functional cells of the organ
APOCRINE
-Gland type? Example?
-released from apical part of cell into DUCT
-Released with some Cytoplasm and PM
ie- lactating mammary gland
-COMPOUND TUBULOACINAR
think of boobs- complicated ductwork system
HOLOCRINE
Gland type? Example?
-Cell debris release into duct after apoptosis
ie- sebaceous glands of integument
BRANCHED ACINAR
MEROCRINE
Exocytosis from apical end into duct
ie- sweat glands of integument
SIMPLE COILED TUBULAR
Type of secretion for each?
Compound tubuloacinar
Simple Branched Acinar
Simple coiled Tubular
CTA-Apocrine (mucus/serous- mammary-submandibular)
SBA- Holocrine- mucus into lumen (stomach)
SCT- Merocrine- eccrine sweat (deep in dermis)
Sebaceous Glands- derived from? classification of gland? Type of secretion? What secreted? Where located?
- derived from epidermis
- branched acinar
- holocrine secretion of sebum (lipid + cell debris) after apoptosis.
- located right next to hair shaft
Sweat glands- 2 types. 2 similarities?
Derived from epidermis
-Simple coiled tubular
-Merocrine
Eccrine- ACh/Small Lumen/Sweat,ABiotic glycoproteins
Apocrine-Norepinep/protein-rich stored in lumen-BIG Lumen
Eccrine Sweat Glands-
3 similar things to apocrine
4 things different: Innervation? product? structure?
- derived from epidermis
- Simple coiled tubular
- Merocrine
1. -stimulated by Sympathetic ACh
2. -Sweat & antibacterial glycoprotein granules
3. -Narrow lumen in duct
4. Three cell types
Apocrine Sweat Glands-
3 similar things to eccrine
5 things different: where? cell types? Innervation? product? structure?
- derived from epidermis
- Simple coiled tubular
- Merocrine
1. Hair follicles of Axilla, Anus, External Genitals
2. One cell type
3. Innervation by sympathetic Norepinephrine
4. Protein-rich secretion can be stored in lumen
5. WIDE lumen
Cell Composition of Eccrine Sweat Glands. 3 type of cells & respective compositions
- Clear Cells (columnar, produce sweat, mitochondria, glycogen, increased surface are of PM, adjacent to intercellular canaliculi)
- Dark Cells (pyramid, antibacterial glycoprotein granules, RER, Golgi, adjacent to lumen)
- Myoepithelial cells (contraction to assist secretion)
Nail structures-
Free edge Nail groove Nail fold (hang nail) Lunula Nail body Eponychium (cuticle)
What part of the nail is epidermal germinative zone? What is hyponychium?
Nail matrix- Located close to the epinychium(cuticle) under the nail root
Hyponychium thick epidermis attaches free edge of the nail
Where is Epidermis derived from?
Where is the DERMIS derived from?
Epidermis-ECTODERM
Dermis- MESENCHYME from:
- Lateral plate mesoderm (limbs/body wall)
- Paraxial mesoderm (back)
- Neural crest (face and neck)
What induces ectoderm to form the epidermis?
BMP4 and FGF
What allows ectoderm to form the neural plate?
Describe the BMP4 concentration gradient and why its important
Noggin, Chordin, Follistatin are expressed by the notochord and inhibits BMP4.
Low BMP4 induces neural plate
Intermediate BMP4 induces neural crest
High BMP4 induces epidermis
The concentration of BMP4 is low in the middle and increases laterally to the outside so that each layer develops correctly.
What two proteins induce sclerotome development?
What protein induces dermatome development?
What induces myotome development?
What does each paraxial layer secrete respectively?
Sclerotome-SSH & Noggin»_space;»[PAX1]
Dermatome- NT-3 »_space;»> [PAX3]
Myotome- WNT »_space;»> [MyoD/Myf5]
SSH,PAX,WNT,NT
SSH-Sonic hedgehog - sclerotome>PAX1
PAX- Paired box genes- dermis
WNT- Wingless-type genes- myotome>MYF5/MyoD
NT-neurotrophin genes- dermatome>PAX3
Lines of Blaschko
1901 derm disorders saw the segmentation lines
What holds all the cells of the epidermis together?
desmosomes and hemidesmosomes. They change and are lost by change in pH.
Why don’t melanocytes have desmosomes?
They migrate- keep moving through cells- at basale level
melanosomes -
Kinesin transport melanin granules “melanosomes” along cytoplasmic processes of melanocyte until it makes contact with a keratinocyte. Keratinocyte phagocytose melanocyte processes in order to take up the melanin granules.
the granules then transported away from keratinocyte interior by dynein.
Cells in the stratum basale
Cells in the stratum spinosum
cells in the stratum granulosum
Basal- keratinocytes, melanocytes
spinosum- merkel cells, langerhans
granulosum-
If you have a problem with ACH release or cholinergic response:
if you have problem with NE or adrenergic response?
produce too much sweat or not enough sweat
Produce too much sweat or not enough
If you have someone who stinks really bad when they sweat what gland can you associate it with?
Apocrine- high protein stored in lumen- bacteria
-large protein in lumen- PUBES - NE-
Develop during PUBERTY
- Eccrine doesn’t smell b/c it has antibacterial glycoprotein granules
- small antibacterial lumen-ACH-3celltypes-merocrine-coiled tubular
3 cells of eccrine sweat glands
Clear- make sweat->intercellular canaliculi>small lumen
(increased mitochondria/glycogen)
Dark- make antibac glycoprotein granules close to lumen
(increased RER/golgi)
Myoepithelial- contract for secretion
What embryological structure inhibits BMP4? what does it release? why important? what is the gradient?
Notochord releases noggin, chordin, follistatin inhibiting BMP4 close toward center
-established gradient has low center BMP4 and increasing BMP4 away from center
Important because bmp4 induces development of structures based on concentration.
Low BMP4- neural plate
Med- Neural crest
High- Epidermis
what layer of epidermis would you see nodes of blizzazaro?
stratum spinosum
Where do you find bipolar neurons? 3 places
Nasal cavity
Inner ear
Retina
3 types of cancer of skin, frequency, seriousness
Basal Cell- most common
Squamous cell- 2nd most common
Malignant melanoma- not as common- Most serious
PSORIASIS
Normal travel time 50-60 days
rapid proliferation is about 7 days in psoriasis
Where vitD production?
Where mitotically active?
vitD- basale-spinosum
mitosis-basale
Stratum granulosum
1-3 cell layers thick
Have nuclei
Squamous
Keratinophyalin granules give it the grainy look
Intermediate filament associated proteins- where are they? how do they work? what do they do? How do you identify them on TEM?
Filaggrin proteins inside Keratohyaline granules- Cause keratin tonofilaments to aggregate into tonofibrils
look like black tadpoles starting to form black fiber tails
What creates the water barrier of the epidermis?
Lamellar bodies next to plasma membranes secrete (exocytosis) into space between Granulosum and corneum
to create a barrier
granulosum cells secrete the lamellar bodies and the membrane is setup just deep to the corneum layer
pro-barrier lipids-lipid enzymes and proteases
