Histology of Epithelia/Connective Tissue Flashcards
Four Basic Tissue Types.
____ – ___or ___ ___
___ ___ – ___ ___
___-___
____ – ___
Four Basic Tissue Types.
ØEpithelia – cover or line surfaces.
ØConnective tissues – support organs
ØMuscle -contractility.
ØNerves – communication.
Characteristics of All Epithelia.
ØCover or line surfaces.
Ø____ ____ of cells.
Ø____ intercellular material.
Ø____ (vascularity)
ØAlways have a ___ ___
ØContain _____ ____ of ____
ØCover or line surfaces.
ØCohesive sheets of cells.
ØLittle intercellular material.
ØAvascular.
ØAlways have a basement membrane.
ØContain intermediate filaments of cytokeratins.
Epithelia Functions
- ØResistant to ___
- Ø___barrier against ____ organisms and other substances.
- _____ barrier - 2 way.
- ____ barrier
- le.g. ____
- ___ ____
- _____ – endocytosis.
- lining of ___, ___ ___
- ____ epithelium.
- ____ - most ____ are derived from epithelium.
Epithelia Functions
ØResistant to abrasion.
ØMechanical barrier against invasive organisms and other substances.
Ø
ØPermeability barrier - 2 way.
Ø
ØImmunologic barrier
le.g. skin
lmucous membranes
ØAbsorption – endocytosis.
llining of lungs, blood vessels.
lintestinal epithelium.
Ø
ØSecretion - most glands are derived from epithelium.
Ø
Other Functions.
____, neuroepithelial cells
- ___, ____ ___
l
Heat___ -minimal in humans.
Ø
_____.
- myoepithelial cells e.g. in salivary glands
_____- melanocyte cells.
Other Functions.
ØSensation, neuroepithelial cells
lTongue, taste buds
l
ØHeat loss -minimal in humans.
Ø
ØContraction.
lmyoepithelial cells e.g. in salivary glands
l
ØPigmentation - melanocyte cells.
Basic Epithelial Structure
ØEpithelial cells are generally ____
____ region
___surfaces
___ region
ØOrganelles located at specific ___ in each cell.
Basic Epithelial Structure
ØEpithelial cells are generally polarized
lApical region
lLateral surfaces
lBasal region
ØOrganelles located at specific locations in each cell.
Surface Specializations.
____
lassociated with cells active in ____
l
____
lAssociated with cells whose function is ___ of ___ material.
•
ØMicrovilli
lassociated with cells active in absorption.
l
ØCilia
lAssociated with cells whose function is movement of surface material.
•
Cytoskeleton
ØCytoskeleton is composed of a filamentous array of ____s that provide a ____ framework for the cell and to ____ material within it.
ØThere four components to the cytoskeleton: ____,____ ___, ___ ___s and ___ ___
Ø
Cytoskeleton
ØCytoskeleton is composed of a filamentous array of proteins that provide a structural framework for the cell and to transport material within it.
ØThere four components to the cytoskeleton: microtubles, thin filaments, intermediate filaments and thick filaments.
Ø
Filament Protein Composition
Protein components include:
____ (Epithelia)
Vimentin (Fibroblasts, endothelial cells, mysenchymal cells)
Desmin & Vimentin (Muscle)
GFAP & Vimentin (Neurons)
Neurofilaments (Neurons)
Lamins A, B &C (Nuclear envelopes)
Filament Protein Composition
Protein components include:
Keratins (Epithelia)
Vimentin (Fibroblasts, endothelial cells, mysenchymal cells)
Desmin & Vimentin (Muscle)
GFAP & Vimentin (Neurons)
Neurofilaments (Neurons)
Lamins A, B &C (Nuclear envelopes
Intercellular attachments.
ØJunctional complex components.
- ___ ___ – a band that ____ around ____ with adjacent cells.
- ___ ___ – an ____ band ___ adjacent cells
- ___ ___- ___, ___ adhesions around cell and ____ area for ___ ___
- ___ ___ - ____ between adjacent cells.
Intercellular attachments.
ØJunctional complex components.
lZonula occludens – a band that seals around contacts with adjacent cells.
lZonula adherens – an adhesion band between adjacent cells
lMacula adherens- desmosome, spot adhesions around cell and attachment area for intermediate filaments.
lGap junction - communication between adjacent cells.
Hemi Desmosomes.
ØBetween an ___ cell and the underlying ___ ___. The other side of the basement membrane is ____ material so there is not __ ___ with another cell.
Ø
ØBetween an epithelial cell and the underlying basement membrane. The other side of the basement membrane is extracellular material so there is not direct contact with another cell.
Ø
Basement Membrane.
- __ ___
- lProduced by the ___ ___
- lLamina
- ___
- ___
- ___ ___
- lProduced by the underlying __ ___ ___
Basement Membrane.
ØBasal lamina
lProduced by the epithelial cells
lLamina lucida
lLamina densa
ØReticular lamina
lProduced by the underlying connective tissue cells
Basal Lamina
ØRemember:
lThe basal lamina always lies at the interface between ___ ___ and __ ___ (fuses to __ ___
lSometimes, __ basal laminas can ___ if there is no intervening ___ ___
Basal Lamina
ØRemember:
lThe basal lamina always lies at the interface between epithelial cells and connective tissue (fuses to reticular lamina)
lSometimes, two basal laminas can fuse if there is no intervening connective tissue
Epithelial Cell Classification.
ØShape of the surface layer of cells:
___ (flattened cells)
___
____
l
ØAccording to number of cell layers
___layer -___ epithelia
lMore than one layer -____ epithelia
Epithelial Cell Classification.
ØShape of the surface layer of cells:
lSquamous (flattened cells)
lCuboidal
lColumnar
l
ØAccording to number of cell layers
lSingle layer - simple epithelia
lMore than one layer -stratified epithelia
Simple Squamous.
ØIn those areas where ___ ___ is essential.
lLining ___ and ___ ___
lLining areas in ___ where gaseous exchange takes place
___ ___ for ____of plasma.
Simple Squamous.
ØIn those areas where rapid diffusion is essential.
lLining blood and lymphatic vessels.
lLining areas in lung where gaseous exchange takes place
lKidney glomerulus for filtering of plasma.
Simple Cuboidal.
Ø
ØIn areas where a little more ___ is required.
___
___ ___
Simple Cuboidal.
Ø
ØIn areas where a little more processing is required.
lGlands.
lKidney tubules.
Simple Columnar
Ø
ØCells that are involved in ___ and ___ of materials
lCells lining the ___ and ___
Simple Columnar
Ø
ØCells that are involved in absorption and processing of materials
lCells lining the small and large intestines.
Pseudostratified.
Ø
)___ of several layers BUT the ___ are at ___ __ and all the cells have a ___ __ to the__ ___
____ tract.
lEpithelium is often known as ____ ____ ___with goblet cells (or as respiratory epithelium).
Pseudostratified.
Ø
ØAppearance of several layers BUT the nuclei are at different levels and all the cells have a direct connection to the basement membrane.
lRespiratory tract.
lEpithelium is often known as pseudostratified ciliated columnar with goblet cells (or as respiratory epithelium).
Stratified Epithelia.
ØThose epithelia with ___ or ___layers of cells.
Ø
ØStratified epithelia are named according to the ___ of the cells on the ____
lStratified squamous.
lStratified cuboidal.
lStratified columnar.
Stratified Epithelia.
ØThose epithelia with 2 or more layers of cells.
Ø
ØStratified epithelia are named according to the morphology of the cells on the surface.
lStratified squamous.
lStratified cuboidal.
lStratified columnar.
Stratified Squamous Epithelia.
ØMultiple layers.
ØCells on the surface are flattened or squamous.
ØThe ___ differentiated cells are adjacent to the ___ ___ and the most differentiated cells are on the ___
Ø
ØTwo functionally distinct types.
lStratified squamous ___
lStratified squamous___ ___
Ø
ØBoth types ___ ___ but the____ of keratinization varies.
Ø
Stratified Squamous Epithelia.
ØMultiple layers.
Ø
ØCells on the surface are flattened or squamous.
Ø
ØThe least differentiated cells are adjacent to the basement membrane and the most differentiated cells are on the surface.
Ø
ØTwo functionally distinct types.
lStratified squamous keratinized.
lStratified squamous non-keratinized
Ø
ØBoth types contain keratin but the degree of keratinization varies.
Ø
Stratified Squamous Keratinized.
___ ___ ____ is their major function but all have a distinct surface layer
____
l
ØThe degree of ___ varies
lThinner epithelium at ____ – provides some ___ and some ___ to abrasion
lThick epithelium on ___ of __ –very ___ fexibility but ___ resistance to abrasion.
Stratified Squamous Keratinized.
ØResistance to abrasion is their major function but all have a distinct surface layer
lSkin.
l
ØThe degree of resistance varies
lThinner epithelium at eyelids – provides some flexibility and some resistance to abrasion
lThick epithelium on soles of feet –very limited flexibility but great resistance to abrasion.
Stratified Squamous Non-keratinized.
____ flexibility but___ resistance to abrasion and ____ by organisms.
____ distinct ___ ___, ____ are found in the surface cells.
ØResistance is due to a ___ ____ maintained by a ___ rate of ___
lEsophagus
___ ___ - buccal mucosa
lVagina
Stratified Squamous Non-keratinized.
ØGreat flexibility but less resistance to abrasion and invasion by organisms.
Ø
ØNo distinct surface layer, nuclei are found in the surface cells.
ØResistance is due to a thick epithelium maintained by a high rate of proliferation
lEsophagus
lOral mucosa - buccal mucosa
lVagina
Stratified Cuboidal.
ØTwo or more cell layers with a cuboidal luminal layer.
lDuct of exocrine ___ glands.
lSome of the larger ___ gland ducts.
Stratified Cuboidal.
ØTwo or more cell layers with a cuboidal luminal layer.
lDuct of exocrine sweat glands.
lSome of the larger salivary gland ducts.
Stratified Columnar
ØSurface cells are columnar
lIn the larger ducts of ___ ___
Stratified Columnar
ØSurface cells are columnar
lIn the larger ducts of salivary glands.
Transitional Epithelium.
ØEpithelium in which the ____ changes with ____ changes
ØCells on the surface have a characteristic ___ luminal surface.
lAlso known as___ cells or ___ cells.
ØCells may be ____
____tract - bladder. The thickness of the epithelium changes to accommodate ____ and allows the bladder to ___
- ___(contracted) state
- ___state
Transitional Epithelium.
ØEpithelium in which the thickness changes with functional changes
ØCells on the surface have a characteristic convex luminal surface.
lAlso known as facet cells or dome cells.
ØCells may be binucleate.
ØUrinary tract - bladder. The thickness of the epithelium changes to accommodate urine and allows the bladder to distend.
lRelaxed (contracted) state
lExtended state
