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22 Cards in this Set
- Front
- Back
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Cell specializations at intercellular surfaces: types, purposes, locations
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1) Occluding/Tight junctions - seal intercellular spaces so that luminal contents cannot penetrate between the cells, located directly below luminal surface
2) Adhering Junctions - bind epithelial cells together, act to anchor cytoskeletons of each cell 3) Communicating junctions |
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Cell specializations at Luminal surfaces
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1) Cilia - microtubles
2) Microvilli - actin 3) Stereocilia – actin |
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Cell specializations at Basal surfaces
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1) Basement membrane
2) Hemidesmosomes |
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Types of Adhering Junctions
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Zonula adherens - actin filaments
Desmosomes (macula adherens, spot adherens) - IF's |
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Tight Junctions: Function, Location, Composition
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Function - seal intercellular spaces so that luminal contents cannot penetrate between the cells
Location - directly below luminal surface Composition Z01, ZO2, ZO3, AF-6 - intracellular Occludin, Claudin - seal two membranes together in intercellular space |
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Zonula Adherens/Adherens Junctions: Function, Location, Composition
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Function - form strong bond between adjacent cells, transcellular network
Location - deep to the zonula occludens Composition - intercellular-CAMs and cadherins; cytoplasmic face-actin filaments; attachment protein-vinculin |
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Desmosomes (macula adherens): Function, Location, Composition
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Function - provide structural integrity; large number in stratified squamous epithelial tissue
Location - deep to adhering junctions; scattered Composition- intercellular-desmocollins; transmembrane-desmogleins; plaque- desmoplakin, keratin |
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Terminal Bar/Junctional Complex
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Zonula Adherens, Zonula Occludens, Desmosomes (check this)
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Gap Junctions: Location, Function, Regulation, Composition
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Location - below junctional complex Function - communication between cells; numerous in embryonic tissues Regulation - Ca2+, pH, cAMP
Composition - connexon-6 transmembrane proteins - connexins-at least 24 known genes |
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What can go through Gap Junctions?
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Ions (+ chg), amino acids, sugar, vitamins, hormones
Permeability affected by pH, Ca2+ ion concentration, cAMP |
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Hemidesmosomes: Function, Location, Composition
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Function- anchorage of cytoskeleton at the base of the cell to the basement membrane
Location- basal plasma membrane Composition- integrins α6β4, laminin 5 |
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Functions of Basement Membrane
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1) Physical support
2) Cell attachment 3) Selective barrier: fibroblasts cannot get through, but lymphocytes can 4) Growth, differentiation 5) Regeneration: scaffolding for nerve, muscle regen. 6) Special functions: ultrafiltration in kidney, blood-air barrier (lung), deterrent of metastasis |
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Composition of Basement Membrane
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1) Type IV collagen - exclusive to basement membrane
2) Laminin - binds collagen to basement membrane 3) Proteoglycans 4) Entactin - binds laminin to type IV collagen 5) Fibronectin - binds integrins of plasma membrane 6) Type VII collagen - binds basal lamina to subjacent collagen |
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Cilia: Structure, function
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Plasma membrane bound axoneme
20 MTs that surround a doublet of microtubules: 9 doublets with dynein arms - ATPase activity; MTs slide longitudinally Inserts into a basal body composed of 9 triplets of MTs Function: Clear airways, move ovum |
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Cilia vs Microvilli
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Cilia: MTs, Tubulin
Microvilli: Thin filaments, Actin |
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Microvilli
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AKA BRUSH BORDER/Striated Border
1 micrometer in length 20-30 actin filaments covered by glycoprotein called glycocalyx contract and elongate to prevent cloggin, but contain no ATPase insert into terminal web which contracts to cause slight movement |
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Stereocilia
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Complete misnomer
Actin filaments (complete this card) |
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Immotile Cilia Sydrome
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Defect in dynein arms that affect ability of cilia to move
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Epidermolysis bullosa
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skin blister resulting from mutations in keratin 5 and 14
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bullous pemphigoid
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autoantibodies against demidesmosome - blisters
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Epithelial cell tymors
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Carcinomas: malignant tumrous from membranous epithelia
Adenocarcinoma: if malignant tissue arises from glandular tissue |
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Basal cell carcinoma
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The one on Dr. Shaw's nose!
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