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76 Cards in this Set
- Front
- Back
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what are the 3 major functions of epithelial cells?
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protection, absorption, secretion
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what are the 3 surfaces of epithelial cells?
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apical (free), lateral, basal
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which two epithelial surfaces are often grouped as one?
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basal and lateral (basolateral)
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what are the 3 types of apical processes found in epithelium?
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microvilli, cilia, stereocilia
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which, cilia or microvilli, are known as the 'brush border'?
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microvilli bc they cannot be seen with a LM
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what is the main role of microvilli?
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absorption
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which cytoskeletal element provides support for microvilli?
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actin
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what is the name for the web of cytoskeleton that anchors microvilli?
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terminal web
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what causes microvilli to split apart, increasing absorption?
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contraction of terminal web (actin filaments)
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what is the main role of cilia?
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motility
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where are the 2 primary locations of cilia in the body?
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respiratory tract, uterine tubes
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which cytoskeletal element provides support for cilia?
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microtubules
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what is the name for the central core of cilia?
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axoneme
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in which pattern of cytoskeleton are cilia constructed?
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9+2 microtubule pattern ( 2 central MTs surrounded by 9 pairs)
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cilia are anchored to epithelial cells via which structures?
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basal bodies
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basal bodies are modifies version of what cellular component?
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centrioles
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are stereocilia longer or shorter than microvilli?
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longer
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true or false. Sterocilia are motile, like cilia.
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false, they are wrongly names and are not motile.
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what are the 3 types of junctions found on lateral surfacs?
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occluding junctions, adhering junctions, and communicating junctions
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what is another name for tight junctions?
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ZO (zona occludens)
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which of the lateral junctions are found closest to the apical surface?
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tight junctions
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what is the primary function of the tight junctions?
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to seal off intercellular space from exterior/lumen
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which of the lateral junctions creates protein 'rafts', sealing them off from other surfaces?
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tight junctions
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binding of what forms the tight junctions?
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transmembrane proteins
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what are the 2 forms of lateral adhering junctions?
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zonula adherens and desmosomes
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what are the 3 components of zonulae adherins?
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transmembrane proteins, anchor proteins, cytoskeleton
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what is the class of transmembrane proteins that provide support in zonulae adherins? What is the more specific kind of protein used here?
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Cell Adhesion Molecules (CAMs); cadherins
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which proteins form the anchor for zonulae adherins?
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catenin
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zonulae adherins are eventually anchored to which kind of cytoskeleton in the cells?
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actin
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which of the lateral adhering junctions does not form a complete ring around the epithelial cells?
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desmosomes
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by what are desmosomes anchored to cell membrane?
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attachment plaques
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what transmembrane proteins are present in desmosomes?
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cadherins
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to which element of the cytoskeleton are desmosomes attached?
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intermediate filaments
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which are stronger junctions, zonulae adherins or desmosomes?
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desmosomes
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what is the name for the communicating lateral junctions?
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gap junctions
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what are the larger and smaller units of gap junctions? How many are present per cell?
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connexins and connexons; six connexins form 1 connexon
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which lateral junctions form the junctional complex?
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tight junctions, zonulae adherins, desmosomes
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what is the name for the 'bar' that can be seen under the microscopr, representing the 3 uppermost lateral junctions?
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terminal bar
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why does the basement membrane stain PAS positive?
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because it has a high concentration of carbohydrate molecules
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what are the major components of the basement membrane?
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proteoglycans, type IV collagen, fibronectin, laminin
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what are the 3 layers of the basement membrane?
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lamina lucida, lamina densa, lamina fibroreticularis
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which two types of adhesion junctions anchor epithelial cells to basement membrane?
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hemidesmosomes and focal adhesions
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which basal junction binds to intermediate filaments?
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hemidesmosomes
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which transmembrane proteins are involved in both hemidesmosomes and focal adhesions?
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integrins
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which element of the cytoskeleton do focal adhesions use to anchor epithelial cells to the basement membrane?
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actin
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what are two diseases that result from the disruption of the basement membrane?
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epidermolysis bullosa and bullous pemphigoid
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what are the 3 major classifications of surface (non-gland) epithelia?
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number of cell layers, shape of cells, presence of surface specializations
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what are the 3 shapes of epithelial cells?
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squamous, cuboidal, columnar
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what are pseudostratified epithelial cells?
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cells that appear to be in layers but are really all anchored at basement membrane in 1 layer. Not all cells reach apical surface.
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what is the name for the epithelial cells that are found in urinary tract and have the capacity to stretch?
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urothelium
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which two surface specializations on epithelia are often mentioned in the naming of the cells?
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keratin and cilia
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where is endothelium found?
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at the interior of blood vessels
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where is mesothelium found?
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lining serous body cavities
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which 2 characteristics are used to classify gladular epithelium?
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number of cells, structure
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which class of glands may have ducts?
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exocrine
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what are the 3 types of ducts present in exocrine glands?
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merocrine, apocrine, holocrine
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which type of gland releases secretory vesicles with plasma membranes? Which releases vesicles without membranes?
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apocrine; merocrine
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which type of gland self-destructs when it releases its secretions?
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holocrine
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what is the classic example of a unicellular gland?
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Goblet cell
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what is the name for glands with more than 1 duct?
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compound
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what are the 3 major gland shapes?
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tubular, acinar, tubuloacinar
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what are the 2 basic forms of endocrine glands?
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cords or follicles
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where is epithelial vasculature located?
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connective tissue
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what covers microvilli? Cilia?
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plasma membrane for both
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which motor protein allows cilia to move?
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dynein
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what is the name for epithelium that has a sensory function (i.e. tongue)?
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neuroepithelium
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what is the name for the type of epithelium cell that contracts?
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myoepithelium
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to which layer of the basement membrane are hemidesmosomes and focal adhesions bound?
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lamina densa
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where could you find simple cuboidal epithelium? ciliated simple columnar? simple columnar with microvilli?
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kidney tubules; respiratory tract; small intestine
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where can you find non-keratinized stratified squamous epithelium?
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esophagus
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where might one find keratinized stratified squamous epithelium?
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skin
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where might one find stratified cuboidal epithelium?
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sweat ducts
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where are the rare stratified columnar epithelia found?
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in transition zones like in the anus.
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where will you normally find pseudostratified columnar epithelium? do they normally have any surface specializations?
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respiratory tract; cilia
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can cilia be present in stratified epithelium?
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no
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what is an example of apocrine gland? holocrine?
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breast milk (mammary glands); sebaceous glands (hair follicles)
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