Histology of Epithelia/Connective Tissue Flashcards Preview

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1

Four Basic Tissue Types.

____ – ___or ___ ___

___ ___ – ___ ___

___-___

____ – ___

Four Basic Tissue Types.

ØEpithelia – cover or line surfaces.

ØConnective tissues – support organs

ØMuscle -contractility.

ØNerves – communication.

2

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.

3

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

4

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.

5

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.

6

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.

7

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

8

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

9

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.

10

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

11

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

12

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

13

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

14

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.

15

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.

16

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.

17

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).

18

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.

19

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

20

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.

21

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

22

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.

23

Stratified Columnar

ØSurface cells are columnar

lIn the larger ducts of ___ ___

Stratified Columnar

ØSurface cells are columnar

lIn the larger ducts of salivary glands.

24

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

25

Specialized Epithelial Cells

Myoepithelial cells

  specialized for____

l

Specialized Epithelial Cells

Myoepithelial cells

  specialized for contraction

l

26

Specialized Epithelial Cells
____epithelial cells
 

___cells

__ ___ cells

 

Specialized Epithelial Cells
Neuroepithelial cells
 

lOlfactory cells

l

l

l

l

lTaste bud cells

l

27

Gland Classification According to:

ØMorphology of the __ ___

  • lSimple coiled tubular etc.

ØType of____:

  • lMucous, serous, mixed

ØMethod of _____

  • lMerocrine
  • lHolocrine
  • lApocrine

Gland Classification According to:

ØMorphology of the duct system.

lSimple coiled tubular etc.

ØType of secretion:

lMucous, serous, mixed

ØMethod of secretion

lMerocrine

lHolocrine

lApocrine

28

Classification by mode of secretion

Holocrine glands - accumulate products until cell ____. example.... ___ glands

Merocrine glands - secrete products (as soon as product are ___) by ____
                                examples....pancreas, sweat, and salivary.

Apocrine glands - ____ of products, then ___ of cell __ ___ example... ___ glands. 

Classification by mode of secretion

Holocrine glands - accumulate products until cell ruptures. example.... sebaceous glands

Merocrine glands - secrete products (as soon as product are made) by exocytosis.
                                examples....pancreas, sweat, and salivary.

Apocrine glands - accumulation of products, then apex of cell pinches off. example... mammary glands. 

29

Goblet Cells – UNICELLULAR gland cells stained to show the mucin.

Goblet Cells – UNICELLULAR gland cells stained to show the mucin.

30

Gland Organization

ØProducts are secreted into ___

ØThen move through series of increasingly ___ ducts

ØSecretory vs. Ductal portions of glands

Gland Organization

ØProducts are secreted into acinus

ØThen move through series of increasingly larger ducts

ØSecretory vs. Ductal portions of glands