Epithelia

Question 1

what lines blood vessels?

Answer 1

endothelium

Question 2

what is keratin?

Answer 2

protein that has waterproof qualities

Question 3

what lines the outside of lungs?

Answer 3

mesothelium

Question 4

what lines abdominal organs?

Answer 4

peritoneum

Question 5

what is the function of epithelia?

Answer 5

barriers for:

• protection
• absorption
• secretion

Question 6

what are the categories of epithelia based on layers of cells?

Answer 6

• simple
• stratified
• pseudostratified
• urothelia/transitional

Question 7

on which type of epithelium would you find cilia/microvilli?

Answer 7

• columnar

Question 8

what is the function of stratified epithelia?

Answer 8

protection from frequent frictional forces

Question 9

describe the lifecycle of cells in stratified epithelia

Answer 9

• start next to basement membrane

- mature as they get pushed further from BM by other cells forming

Question 10

what are the types of simple epithelia?

Answer 10

• simple squamous
• simple cuboidal
• simple columnar

Question 11

what are the types of stratified epithelia?

Answer 11

• stratified squamous non-keratinising

- stratified squamous keratinising

Question 12

describe the lifecycle of cells in pseudostratified epithelia

Answer 12

• start at basement membrane

- replaced by lateral migration

Question 13

describe the structure of urothelia

Answer 13

• looks stratified, but is pseudostratified

- single layer of umbrella flattened cells on top bound by junctions (waterproofing)

Question 14

where is urothelia found?

Answer 14

collecting part of urinary tract

Question 15

what is the composition of basement membranes?

Answer 15

• collagen IV
• fibronectin
• other extra-cellular proteins

Question 16

what stain can be used to see basement membranes?

Answer 16

periodic acid schiff

Question 17

what are the types of epithelial junctions?

Answer 17

• occluding (tight)
• desmosomes (anchoring/adherent)
• gap (communicating)

Question 18

what is an occluding junction?

Answer 18

band-like fusions between cells that do not let most molecules through

Question 19

what is a desmosome?

Answer 19

plaque that forms physical joins between cells and connects the cytoskeletons of adjacent cells
- spreads forces across several cells

Question 20

where are desmosomes found?

Answer 20

sites exposed to abrasive forces

e.g. skin

Question 21

where can hemidesmosomes be found?

Answer 21

binding epithelial cells to basement membrane