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Epithelia and Glands
Epithelia and Glands
25
Histology
Professional
09/24/2011

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Term
Epithelia origin
Definition
embryonic tissues- ectoderm, mesoderm, and endoderm
Term
Characteristics of epithelia
Definition
1. surface covering
2. highly cellular
3. tightly adherent
4. polarized
5. highly rengerative
6. rests upon a basement membrane
7. avascular
8. gives rise to the parenchyma of glands
Term
Functions of epithelia
Definition
1. protection
2. transport
3. secretion
4. excretion
5. absorption
6. lubrication
7. reception (sensory)
Term
Cell coat, "Fuzzy" coat formed by the sugar chains of glycoproteins and glycolipids on the external surface of cell membrane
Definition
Glycocalyx; appears fuzzy with EM
Term
Importance of glycocalyx
Definition
role in adhesion of epithelial cells to each other and to the extracellular matrix; vital to cell-cell recognition
Term
Epithelia rests upon a specialized layer of extracellular matrix called _____ _____ and consists of two layers: ________ and ______
Definition
Epithelia rests upon a specialized layer of extracellular matrix called basement membrane and consists of two layers: basal lamina and lamina reticularis
Term
Basal lamina is synthesized by ____ cells and contains type ___ and ___ collagen, ___ and ___ (glycoproteins), and ____ (e.g. heparin sulfate)
Definition
Basal lamina is synthesized by (epithelial) cells and contains type (IV) and (VII) collagen, (laminin) and (fibronectin)(glycoproteins), and (proteoglycans)(e.g. heparin sulfate)
Term
Lamina reticularis is the underlying mat of type ___ collagen and is synthesized by ____ of connective tissue
Definition
Lamina reticularis is the underlying mat of type (III) collagen and is synthesized by (fibroblasts) of connective tissue
Term
What structures form the ahesion of epithelial cells with the basal lamina?
Definition
Transmembrane proteins form linkages w/ glycoproteins of the basal lamina.
Term
Type ___ collagen stabilizes the basal lamina while type ___ collagen links it with the lamina reticularis.
Definition
Type (IV) collagen stabilizes the basal lamina while type (VII) collagen links it with the lamina reticularis.
Term
The following functions are characteristic of what cellular structure?
1. Limit the passage of materials crossing the epithelial sheet between cells
2. Reinforce the adhesion of cells to each other
Definition
Junctional complex also known as terminal bar when viewed under LM.
Term
The element of the junctional complex that is composed of an anatomosing system of ridges extending around the perimeters of neighboring cells in a belt-like fashion that functions to restrict the passage of molecules between cells is known as the ___ ___.
Definition
Zonula occludens (tight junction)
Term
What transmembrane (integral) protein interlocks with each other across the intercellular space restricting the passage of molecules between cells?
And what element of the junctional complex does it form?
Definition
occludens; zonula occludens
Term
What integral protein bridges the intercellular space to enhance adhesion by connecting to bundles of actin microfilaments on the cytoplasmic side?
What element of the junctional complex does this form?
Definition
cadherins; zonula adherens
Term
What element of the junction complex is characterized by disc-like plaques of e- dense material on the cytoplasmic side of the membrane which act as attachment sites for tonofilaments and also has cadherens to establish linkages between cell membranes, both of which provide mechanical stability?
Definition
Macula adherens (Desmosomes); hemidesmosomes which are present along cell surfaces facing the basement membrane
Term
What type of intercellular connection allows for bidirectional exchange of small molecules and ions between cells?
This connection is formed by integral proteins called ____.
Definition
Gap junctions; connexons
Term
Simple squamous epithelium lining blood and lymphatic vessels and the heart is also called ___.
Definition
endothelium
Term
Simple squamous epithelium lining the body cavities is also called ____.
Definition
Mesothelium
Term
What may occur to stratified squamous epithelium on dry or severely abraded surfaces such as skin?
Definition
They may become keratinized
Term
The nucleus of the superficial cells of transitional epithelium are often (bilobed/binucleated)?
Definition
binucleated
Term
Where are transitional epithelium exclusively found?
Definition
urinary bladder, ureter, and renal pelvis
Term
Match the following:
1. the functional epithelial portion
2. the supporting connective tissue portion of epithelium

a. Parenchyma
b. stroma
Definition
1. a
2. b
Term
Match the following:
1. gland that discharges its products to the original surface by a persisting cord of cells that serve as a duct
2. Gland that looses continuity with the original surface and discharge their product into the bloodstream

a. endocrine gland
b. exocrine gland
Definition
1. b
2. a
Term
Match:
1. serous glands
2. mucous glands

a. contain a round nucleus
b. contain a flattened nucleus in the basal part of the cell
c. is largely non-staining
d. basal portion is basophilic and apical portion is acidophilic
Definition
1. a, d (zymogen granules stain well with eosin if well preserved)
2. b, c (due to loss of the water soluble mucous product)
Term
Match:
1. merocrine (eccrine) secretion
2. holocrine secretion
3. apocrine secretion

a. entire cell and contents are released; sebaceous glands
b. secretory product synthesized is extruded from the cell without loss of any part of cell, a good example of exocytosis
c. secretory product is released from the cell w/ a varying amount of the apical cytoplasm of the cell; participate in the formation of milk and in large sweat glands in the axilla
Definition
1. b
2. a
3. c
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