Karteikarten
Epithelium
Karten in diesem Stapel (42)
- 1What are the 2 major forms that epithelia can be present in1 - surface - sheets of cells that cover external surfaces and line internal surfaces of body
2 - glandular - secretory cells of glands - 2What 2 ways can epithelia be classifiedby number of layer and shape of cells
- 3What are the classifications by layer number1 layer = simple
multiple layer = stratified - 4What are the classifications by shape and describe the appearance of each1 - squamous - flattened
2 - cuboidal - length and width similar
3 - columnar - length>width - 5What are the properties of simple squamous epithelium- single layer of flattened cells
- occurs in many organs e.g. large body cavities, heart, blood vessels, lymph vessels
- nuclei of epithelial cells often flattened/oviod and close to centre of cells - 6What are the properties of simple cuboidal epithelium- cells appear cuboidal in section perpendicular to surface of epithelium
- occurs in small excretory ducts of many glands, follicles of thyroid gland, kidney tubules, surface of the ovaries - 7What are the properties of simple columnar epithelium- cell height taller than cell width
- nuclei of cells are located at the same height within cells - often close to base
- example - simple columnar that lines internal surface of s and l intestine - 8Explain 1 limitation of histology2D representation of 3D structure - depends in angle between plane of the section and plane of surface of epithelium
- oblique sections = visible in all slides of organ in which epithelium lines a surface with an irregular profile
- section - perpendicular to plane of epithelial - columnar epithelial but if plane is oblique to plane of epithelial - nuclei will be diff shapes - 9How can this problem be overcomelook at shape, location and spacing of nuclei
- 10What epithelia is found in the blood vessels and give properties of this type Give 1 limitation of blood vessels under histology- lined by simple squamous epithelium with few exceptions
- flattened and form much larger part of surface
- flattened nuclei, darkly stained
- not every nucleus present in section
- limitation - capillaries and small vessels are easily deformed during tissue processing = damaged epithelium - 11What epithelia is found in the small intestines lining and give properties of this type- simple columnar
- involved in absorption of components of digested food in lumen of intestine
- complex folds - increase surface area for absorption - 12Give another cell type of this epithelium and describe how these appear histologically- mucous producing goblet cells
- mucus stains weakly or not at all with H&E
- round, light hollows represent apical cytoplasm of goblet cells which is filled with mucin containing secretory vesicles - 13What are the properties of stratified squamous epithelium- deepest cells - in contact with basement membrane
- cuboidal or columnar in shape
- at surface of epithelium - appear flat - 14What does the name given to epithelium depend onthe shape of cells on surface
- 15How do keratinised layers arise and give 2 advantages of this- most apical layers of cells are dead and lose nucleus and cytoplasm
- contain tough, resistant protein = keratin
+ = makes epithelium waterproof
+ = provides protection from mechanical damage e.g. lining of oral cavity coming into contact with food - 16Give the names of 2 types of epithelial that are difficult to classify using cells in surface layer and cell layer numberPseudostratified and transitional
- 17Give the properties of transitional epithelium- found exclusively in the excretory urinary passages
- shape of cells in surface layer depends on the degree of distension of organ with a lumen lined by this type - 18How does the appearance of epithelium differ in relaxed and distended statesrelaxed - formed by many cell layers
- most basal - cuboidal/columnar shape
- several layers of polyhedral cells and layer of superficial (domed, convex luminal surface)
distended - only 1 or 2 layers of cuboidal cells covered by superficial layer of large, low cuboidal or squamous cells
- resemble stratified squamous - 19What are the properties of pseudostratified columnar epithelium and give the location- all cells in contact with basement membrane but not all reach epithelium surface
- nuclei - widest part of cell
- nuclei of cells which do or do not reach the surface of the epithelium are often located at different heights within the epithelium and give a stratified appearance
- looks stratified but is not
- found in the excretory ducts of glands - 20Give the 3 epithelial cell surfaces and their locations1- apical - free surface facing lumen
2 - lateral - contact with neighbouring cells
3 - basal - rests on basemement membrane - 21What is the basement membrane- epithelia separated from conn tissue by extracellular supporting layer
- comprised of ECM
- membrane proteins of epithelial cells anchored in basement membrane
- acts as selectively permeable filter between epithelium and conn tissue - 22Give 3 structures that can be found on the apical surface1 - cilia
2 - microvilli
3 - sterocilia - 23What are the properties of microvilli and stereocilia- non-motile finger- or thread-shaped extensions of epithelial cells
- increase the surface area of cells in
absorption
- microvilli much shorter than stereocilia - 24What is the function of cilia- motile structures that beat in a synchronous manner to move
material across epithelial surfaces - 25Give the 3 types of junctional complexes1 - occluding
2 - adhering
3 - communicating - 26What is the function of occluding type complexes- tight junctions
- connects adjacent cells
- close to apical surface
- forms rings around individual cells with neighbouring cells surrounding
- stops material dropping down between cells into basement membrane - 27What are the 2 types of adhering type complexes and their function- desmosomes and hemidesmosomes
-desmosomes and zonulae adherens = anchor cells to each other
- connected to cytoskeleton
- hemidesmosomes = connect cells to basement membrane
- form network of cells due to connection to cytoskeleton - 28What is the function of communicating type complexes- gap junctions
- allows movement of small molecules from one cell to adjacent - 29Define glands- individual cells or aggregations responsible of secreting substances
- 30What is the difference between exocrine and endocrine glandsexocrine - release secretory product e.g. milk, sweat, mucus via system of ducts that open onto surfaces of body in contact with external world
endocrine - release secretory product into spaces between secretory cells from which it enters bloodstream - 31How are exocrine and endocrine glands derived- developmentally derived from epithelia that grow into the underlying connective tissue
- develop the special characteristics of the mature gland
- exocrine = maintain connection with surface epithelium
- endocrine = connection is lost - 32What 3 ways are exocrine glands classified1 - morphology
2 - mode of secretion
3 - nature of secretion - 33How are exocrine gland classified morphologicallysimple vs compound
tubular vs alveolar/acinar secretory unit - 34What 3 ways can secretory cells form1 - tubes in tubular glands
2 - acini in acinar glands
3 - alveoli in alveolar glands - 35What are the 3 types of gland secretionmecrocrine
apocrine
holocrine - 36What is merocrine secretion- corresponds to the process of exocytosis
- vesicles open onto the surface of the cell and secretory product is discharged
- no further loss of cell substance - 37What is apocrine secretion- part of the apical cytoplasm of the cells is lost together with the secretory product
- continuity of the plasma membrane is restored by the fusion of broken edges of the membrane
- cell is able to accumulate the secretory product anew
- mechanism used by apocrine sweat glands, mammary glands and prostate - 38What is holocrine secretiondesignates breakdown of entire secretory cell
- seen in sebaceous glands of skin - 39How does smooth muscle appear histologically- no striations
- mononuclear cells
- shape of cells and nuclei shape look different - 40How does cardiac appear histologically- mononuclear
- striations - contractile part
- presence of intercalated discs - 41What are intercalated discs- junctional complexes
- communication junctions that allow transfer of ions from one cell to another
- allow contractility - 42How does skeletal muscle appear histologically- striations
- multinucleated cells
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- Veterinary bioscience - Cells to systems Karteikarten am Epithelium, erstellt von Teresa Richards am 03/03/2018.
- Erstellt von
- Teresa Richards
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