Term
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Definition
-avascular -composed of polyhedral cells -cover/lines body surfaces -forms secretory portions and ducts of gland -constitute special sense receptors -rests on basal lamina (continuous etracellular layer) -all 3 (endoderm, ectoderm, mesoderm) germ layers |
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Term
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Definition
-segregation of the surface or luminal environment -segregation of the surrounding connective tissue -act as selective permeability barrier 1. protection (against trauma and internal drying)
2. secretion (of clotting factors)
3. absorption (in GI and urinal tract)
4. transport (of molecules)
5. receptor function (nerve endings)
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Term
| 3 characteristics of epithelium |
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Definition
1. closely arranged and interconnected by junctional complexes 2. show morphologic and functional polarity EXCEPTION: majority of endocrine glands lack an apical surface 3. lie upon a basement membrane
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Term
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Definition
A single layer of cells a. squamous b. cuboidal c. columnar d. pseudostratified |
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Term
| Simple Squamous Epithelia |
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Definition
-secretory and transport -surface layer flat -includes mesothelium(lines body cavities; lubricates) -includes endothelium(lines blood vessels; gas transport) |
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Term
| Simple Cuboidal Epithelia |
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Definition
-largely in ducts -absorpative function in kidney |
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Term
| Simple Columnar Epithelia |
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Definition
-nuclei polarized to basal portion or middle of cell -in GI tract for protection and absorption |
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Term
| Stratified Epithelia and its layers |
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Definition
-multiple cell layers a. Basal layer (stratum basale/germanativum) -one cell layer thick on basal lamina b. Polygonal layer (spinous layer; stratum spinosom) -only in stratified squamous -several cell layers thick c. Surface layer (name of tissue) -stratified squamous, cuboidal, columnar epithelium or transitional epithelium
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Term
| Stratified squamous epithelium |
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Definition
-flatten out towards surface -all three layers present (basal, polyonal, surface) can be 1. non-keratinized 2. keratinized a. parakeratinized b. orthokeratinized
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Term
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Definition
-on wet surfaces; surface cells are vital ex. mouth and vagina -cells are flat -for protection and flexibility -characteristic of mucosal surface |
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Term
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Definition
-abundant keratin -stiffens cell -for things that encounter abrasive surfaces -stains intense pink (like pink highlighter) -parakeratinized or orthkeratinized |
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Term
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Definition
-nucleus is present at surface (has not broken down)
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Term
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Definition
-lacks nucleus at surface (it has broken down) -slowly formed |
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Term
| Stratified cuboidal epithelium |
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Definition
-2 layers of cells first basal then cuboidal -found in ducts -good for secretion and absorbtion |
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Term
| Stratified columnar epithelium |
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Definition
-basal layer then layer of columnar -in ducts of glands -good for secretion and protection |
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Term
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Definition
-in urinary tract -can go between two states relaxed = bladder empty stretched = bladder full
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Term
| Surface Specializations (3 domains) |
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Definition
-exhibit polarity that divides into 3 domains ->apical = faces tissue surface or lumen (top) ->lateral = faces adjacent epithelial cells (wraps around surface) ->basal = faces basement membrane (bottom)
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Term
| Apical Surface Modifications (4 total) |
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Definition
1. microvilli 2. cilia 3. sterocilia 4. flagella |
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Term
Apical Surface Modifications - Microvilli Structure |
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Definition
NON-MOTILE hair-like cellular surface extensions -increase surface area for absorption -core of actin filaments anchored to villin (protein) -actin (in apical cytoplasm) blends into terminal web -actin filaments cross-linked by fascin and fimbrin -strengthen microvillus core -attached to cell membran by myosin I
-covered by glycocalyx |
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Term
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Definition
-acellular coatingcoverin microvilli -known as brush border in renal proximal tube -known as striate border in intestine -has digestive enzymes -stains PAS + (intense pink) |
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Term
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Definition
elongated (longer than microvillie) MOTILE surface extensions found in: -respiratory tract -oviductsrete testis -hair cells of ears function to sweep surfaces clean and move mucose synchronous action propels fluid/particles one way -rapid depol and repol of tubules -down-up; down-up; down-up |
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Term
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Definition
-microtubules in a "9+2" arrangement (2 central surrounded by 9 pairs) -oriented along long axis of cilium -insert into basal bodies (modifies centrioles) below cell membrane |
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Term
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Definition
-NOT CILIA-->modified microvilli -very long NON-MOTILE -Present in: -epidiymis -proximal ductus deferens -hair cells of ears -for absorption or sensory reception
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Term
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Definition
elogated cilium for propulsion in sperm only in males extremely motile |
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Term
| Lateral Surface Modifications (3 total) |
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Definition
holds cells together and function in communication 1. Junctional (adhesion) complexes 2. Gap Junctions 3. Processes |
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Term
Junctional (adhesion) complexes 3 complexes |
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Definition
-hold cells together -stop movement of fluids from tissue surface into intercellular space 1. zonula occludens (tight junctions) 2. zonula adherens 3. macula adherens (desmosome) |
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Term
Zonula Occludens (Tight Junctions) |
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Definition
-most apical -prevents flow of material between adjacent cells -prevents specialized apical membrane protiens from migrating to lateral cell membrane -composed of fused cell membranes -linked by occludin (transmembrane protein) -under light microscope both zonulas appear as terminal bar near apex of cell
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Term
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Definition
-anchors cell to neighbor via actin filaments (connects cytoskeleton of one cell to another) -encircles cell and is continuous w/terminal web -transmembrane protein E-cadherin binds to a complex linking it with cytoskeletal actin -under light microscope both zonulas appear as terminal bar near apex of cell |
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Term
Macula Adherens (desmosome) Attachment Plaques |
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Definition
-forms tight cell-to-cell adhesion -consists of matching disc-like structures on adjacent cells -has internal attachment plaques made of: --> desmoplakins --> plakoglobins -they are proteins that anchor intermediate filaments (cytokeratin) that go from: cytoplasm -> attachment plaque -> cytoplasm intercellular space b/w plaques has glycoproteins called desmogleins and desmocollins
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Term
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Definition
-structural unit of precisely aligned pores -movement of molecules b/w adjacent cells -enables cells to act as functional unit -consists of: -channels formed by connexons -connexons composed of 6 connexins in circle -structures may open or close
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Term
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Definition
dendtritic extensions axons dendrites |
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Term
| Basal Surface Modifications (4 total) |
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Definition
PAS + -surrounds cell types that contact connective tissue ex. epithelium, smooth muscle, Schwann, adipocytes 1. basal lamina 2. reticular lamina 3. hemidesmosome 4. focal adhesion |
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Term
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Definition
-attachment sites for cells and adjacent connective tissue -composed of: type IV collagen glycoproteins (lamina, entactin, fibronectin) proteoglycans (heprine sulfate, chondroitin sulfate) -lowest epithelial level -attached to underlying connective tissue via type VII collagen and dermal elastic system |
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Term
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Definition
1. regulation of cellular proliferation and differentiation (tells daughter cells to move away) 2. scaffold for migration (migrates towards self to heal cuts) 3. determination of cell polarity 4. organization of cell membrane proteins (for signal transduction) 5. attachment 6. filtration |
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Term
| Basal Lamina Subdividions |
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Definition
1. lamina lucida - contains extracellular regions of adhesion molecules 2. lamina densa |
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Term
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Definition
-below lamina densa -basal lamina in close association with reticular fibers -in areas subject to friction and force |
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Term
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Definition
-attachment between epithelial cells and basement membrane via cytokeratin intermediate filaments -in areas of srong abrasion -intermediate filaments insert into 1 attachment plaques -integrins and type XVII collagen link structure to basal lamina |
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Term
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Definition
-attachment between epithelial cell and basement membrane via cytoskeletal actin filaments and integrins
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Term
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Definition
-serve a secretory function and deposit product onto epithelial surface
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Term
| Method of Secretion of Exocrine Glands |
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Definition
1. Merocrine - vesicles fuse w/cell membrean and empty product (secretory cell remain intac) --> most glands; no loss of cell membrane 2. Apocrine - loss of apical portion of cytoplasm -->mammary, cerumen, sweat glands -->cell losses volume -->viscous secretion 3. Holocrine - degeneration and discharge of entire cell (sebaceous glands) -->waxy secretion |
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Term
| Unicellular Exocrine Glands |
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Definition
1. Goblet Cells - secrete mucose PAS + 2. Mucose secreting Epithelial cells of STOMACH
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Term
Multicellular Exocrine Glands 2 kinds |
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Definition
-from localized epithelial proliferations into underlying connective tissue -exhibit controlled cell death to form hollow structures Simple Glands = single unbranched duct Compund Glands = multiple branched ducts |
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Term
Multicellular Exocrine Simple Glands (4 types) |
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Definition
Single Unbranched Duct 1. Tubular - hollow cylindar; no excretory duct ex. intestinal crypts 2. Coiled Tubular - colied tube with excretory ducts ex. sweat glands 3. Branched Tubular - branching at terminal tubule ex. gastric glands of stomach 4. Acinar (Alveolar) - spherical units surround small lumen a. unbranched = seminal vesicles b. branched = sebaceous glands
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Term
| Compound Glands - Gland Organization |
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Definition
Multiple branched ducts a. may be divided into lobes b. each lobe surrounded by fiberous capsule c. septa from capsule divide each lobe into microscopic lobes d. each lobule is equivalent to a simple gland e. each lobule is drained by intralobular ducts
f. intralobular ductsdrain into interlobular (interlobar) ducts in fibrous interlobar septa
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Term
| Compound Glands - Secretory Portion |
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Definition
a. tubular - usually coiled (mucose glands of stomach) b. acinar (alveolar) - (small glands of respitory tract) c. tubulo-acinar - tubules and acini (large salivary glands) d. saccular - (mammary glands) |
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Term
| Compound Glands - Duct Organization |
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Definition
a. lobule - intercalated ducts lead to intraloular ducts (single intralobular duct drains lobule) b. lobe - interlobular ducts (in septa) receive intralobular ducts c. glands - lobar ducts frain lobes into main duct |
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Term
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Definition
1. Serous Cells 2. Mucous Cells 3. Mixed |
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Term
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Definition
-surround narrow lumen -nucleus rounded at base of cell -refractile cytoplasmic and secretory granules -cell boundaries poorly defined -stain looks very granular -stains basophilically |
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Term
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Definition
-surround wide lumen -nucleus flattened at base of cell (jammed at base)
-pale cytoplasm mucigen droplets lost in tissue prep -cell boundaries sharply defined -foamy in appearence |
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Term
Mixed Cells Grapes Example |
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Definition
-both serous and mucous cells -serous demilunes on mucse acini
-modify secretion of mucose Grapes = acini Stem = ductal system |
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