Epithelial Specializations and Exocrine Glands Flashcards Preview

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Flashcards in Epithelial Specializations and Exocrine Glands Deck (28):
1

Domains of epithelial cells

apical, lateral and basal

2

Domain functions

Responsible for establishment and maintenance of cell polarity

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Micro-villi - Structure

Small (1 millimeter) finger like extensions of apical membrane.
Project into lumen.
Possess actin filaments.
Anchored into terminal web.

4

Micro-villi - Function

increase cell surface area

5

Micro-villi - example location

intestinial absorptive cells

6

Setreocillia - Structure

NON-MOTILE microvilli.
Long (10-25 millimeter) finger like extensions of apical membrane.
Project into lumen.
Possess actin filaments.
Anchored into terminal web.

7

Cilia - Structure

Hair-like projections.
Large 0.2 um diameter/10um length
MOTILE
axoneme
9 + 2 arrangement

8

axoneme

microtubles core (tubulin dimers)

9

Cilia - Function

W/ Dynein, move substances across surface of epithelial layer

10

Flagella

Microtubular core in Spermatoza

11

Cilia Disorders

Primary ciliary dyskinsiea
Kartageners syndrome
Youngs syndrome

12

Primary ciliary dyskinseia

immotile cilia syndrome

13

Kartageners syndrome

cilia lack dynein

14

Youngs syndrome

cilia have malformed radial spokes and dynein arms

15

Lateral Domain - Structural components

cell to cell junctions

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Lateral Domain - Function

attachment
exchange of small molecules
regulation of the movement of materials across epithelial layer (apical basal)

17

Lateral Membrane - Structure

terminal bars

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terminal bars

junctional complexes (visible in light microscope)

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Junctions - types

Tight Junction
Adhering Junction
Desmosome

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Tight Junction a.k.a

Zonula Occludens

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Adhering Junction a.k.a

Zonula Adherens

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Desmosome a.k.a

Macula Adherens

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Tight Junction - Structure

close to apical surface
belt-like structure encircle circumference
system of membrane folds
mediated by occludin and claudin/cadherins

24

Tight Junction - Function

-Prevent free flow water soluble molecules between cells
-Compartmentalize integral membrane proteins into apical and basolateral domains

25

Adhering Junction - Structure

Adjacent and basal to zonula occuldens
belt-like structure encircle circumference
Uniform distance between adjacent membrances
Mediated by cadherins/catenins

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Adhering Junction - Function

cell adhesion
link actin cytoskeleton of adjacent cells

27

Desmosomes - Structure

basal to belt junctions
Distributed randomly along domain
Attachment Plaques (Paired thickened membrane region)
Dense material in intercellular space
Associated with intermediate filaments of cytokeratin

28

Desmosomes - Function

Spot Adhesions - strong to disperse shearing forces on cell membrane