Epithelial Specializations and Exocrine Glands

Question 1

Domains of epithelial cells

Answer 1

apical, lateral and basal

Question 2

Domain functions

Answer 2

Responsible for establishment and maintenance of cell polarity

Question 3

Micro-villi - Structure

Answer 3

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

Question 4

Micro-villi - Function

Answer 4

increase cell surface area

Question 5

Micro-villi - example location

Answer 5

intestinial absorptive cells

Question 6

Setreocillia - Structure

Answer 6

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

Question 7

Cilia - Structure

Answer 7

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

Question 8

axoneme

Answer 8

microtubles core (tubulin dimers)

Question 9

Cilia - Function

Answer 9

W/ Dynein, move substances across surface of epithelial layer

Question 10

Flagella

Answer 10

Microtubular core in Spermatoza

Question 11

Cilia Disorders

Answer 11

Primary ciliary dyskinsiea
Kartageners syndrome
Youngs syndrome

Question 12

Primary ciliary dyskinseia

Answer 12

immotile cilia syndrome

Question 13

Kartageners syndrome

Answer 13

cilia lack dynein

Question 14

Youngs syndrome

Answer 14

cilia have malformed radial spokes and dynein arms

Question 15

Lateral Domain - Structural components

Answer 15

cell to cell junctions

Question 16

Lateral Domain - Function

Answer 16

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

Question 17

Lateral Membrane - Structure

Answer 17

terminal bars

Question 18

terminal bars

Answer 18

junctional complexes (visible in light microscope)

Question 19

Junctions - types

Answer 19

Tight Junction
Adhering Junction
Desmosome

Question 20

Tight Junction a.k.a

Answer 20

Zonula Occludens

Question 21

Adhering Junction a.k.a

Answer 21

Zonula Adherens

Question 22

Desmosome a.k.a

Answer 22

Macula Adherens

Question 23

Tight Junction - Structure

Answer 23

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

Question 24

Tight Junction - Function

Answer 24

• Prevent free flow water soluble molecules between cells

- Compartmentalize integral membrane proteins into apical and basolateral domains

Question 25

Adhering Junction - Structure

Answer 25

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

Question 26

Adhering Junction - Function

Answer 26

cell adhesion | link actin cytoskeleton of adjacent cells

Question 27

Desmosomes - Structure

Answer 27

``` 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 ```

Question 28

Desmosomes - Function

Answer 28

Spot Adhesions - strong to disperse shearing forces on cell membrane