Epithelial Tissue III (exam 1)

Question 1

what are microvilli supported by

Answer 1

Cross-linked actin bundles

Question 2

Are microvilli motile

Answer 2

No

Question 3

Microvilli tend to form what cross the apical membrane

Answer 3

Brush border

Question 4

What is microvilli primary function

Answer 4

to increase the surface are of absorption

Question 5

Where are microvilli typically found

Answer 5

on the intestinal epithelium and on parts of renal tubules

Question 6

what is the microvilli core composed of

Answer 6

Actin filament which extends into the terminal web

Question 7

What is the terminal web

Answer 7

A network of cytoskeletal proteins (such as keratins) under the apical membrane of the cell

Question 8

The distal end of the actin filament core in microvilli is capped by _______ and what is the caps function

Answer 8

Formin
Formin interacts with the barbed ends of the actin filaments
Formin regulates the assembly of the actin filaments at the barbed ends

Question 9

The actin filaments that make up the core of the microvilli are cross-linked by what

Answer 9

Villain and fimbrin

Question 10

what is the structure of a cilium

Answer 10

9 peripheral doublets with a central pair of microtubules

- each doublet consists of alpha tubule and beta tubule

Question 11

Describe the structure of the alpha tubule in each of the 9 peripheral doublets of a Cilium

Answer 11

13 protofilaments
Radial spokes extending to sheath around central pair
Pair of dyne arms projecting to beta unit of next doublet

Question 12

Describe the structure of a beta tubule in each of the 9 peripheral doublets of a Cilium

Answer 12

10-11 protofilaments

Question 13

What do cilia develop from

Answer 13

Basal bodies