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29 Cards in this Set
- Front
- Back
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What is the overall organization of epithelial cells?
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Form sheets, unlike CT
Can be single layered or multilayered |
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Can you see intercellular matrix or fibers in LM?
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No
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In what (EM or LM) can you see the specialized junctions between epithelial cells?
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EM
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Function of junctions
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1. Provide mechanical support
2. Establish functional difference between apical and basal compartments of the sheet and the individual cells. |
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Polarized epithelial cells means?
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There is an apical and basal portion of the cell
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Apical portion of cell
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The interior of the lumen it lines or the outer surface it covers
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Basal portion of the cell
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The basement membrane which it rests
Separates the epithelium from other tissues |
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How are epithelia classified?
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The shapes of their cells and the number of cell layers within the epithelial sheet
The shape & position of nucleus |
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Glands
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-Type of secretions: Serous or mucous
-Arrangment of cells: tubular or acinar -Degree of complexity: simple or branched -Presence of absence of specialized ducts. |
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Occluding junctions (zonula occludens and tight junctions)
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-small intercellular space
-always the most apical -fuse at "kisses" |
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Zonula adherens
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-located under occluding jxns
-"belt-like" |
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Desmosome or macula adherens
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-located under zonula adherens
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Hemidesmosome
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-links epithelium to basal lamina
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Junctional complexes
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The ensemble of junctions common in epithelial sheets
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Microvilli
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-geared toward increased surface area & motility
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Cilia
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Motility, help move materials in airway or lumen
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Basolateral folds
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-includes: intercellular contact between epithelial cells, intercellular junctions, basal junctions between epithelium and basal lamina
-large surface area -many mitochondira |
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Simple squamous
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-flat
-1 layer -found in areas of high rate transport -Endothelium: lining of blood & lymph vessels |
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Simple cuboidal
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-cube-shaped with round, central nucleus
-secretory or absorptive |
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Simple columnar
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-cells are taller than wide
-round nucleus in basal compartment -secretory or absorptive |
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Psuedostratified columnar
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-multiple cell types
-different heights -nuclei with different placement -may look layered, but still a single layer -all cells attached to basal lamina, but may not reach apical surface -In trachea, bronchii, male repro. tract |
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Simple stratified
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-stem cells located in basal layer
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Stratified squamous, non-keratinized
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-impermeable barrier
-vagine & esophagus |
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Stratified squamous, keratinized
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epidermis
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Stratified cuboidal/coumnar
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-line ducts
-not very permeable, involved in structural support |
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Transitional
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-multiple layers of round or polygon cells
-cells can be binucleate |
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Metaplasia
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-transformation of epithelium type due to changes in environment
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Endocrine
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discharge product to underlying CT
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Exocrine
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discharge product to outside the lumen or to a duct that empties into a lumen
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