H2 -Covering epithelia

Question 1

What is the basil lamina?

Answer 1

sheet like projection of extracellular matrix on the basal surface

Question 2

What are the functions of epithelia?

Answer 2

line surface - lining of the gall bladder

make organs - livers

Question 3

What are the embryonic origins if epithelium?

Answer 3

ectoderm
mesoderm
endoderm

Question 4

What are the functions of the epithelium?

Answer 4

mechanical barrier 
chemical barrier 
absorption 
secretion 
containment 
locomotion 
sensation and contractility

Question 5

What are the main components of the cytoskeleton?

Answer 5

actin filaments
intermediate filaments
microtubules

Question 6

what is the endoderm?

Answer 6

germ layer gives rise to the epithelia of the gut, respiratory tract, liver and epithelial glands associated with the gut

Question 7

what do actin filaments do?

Answer 7

• Anchorage,

- movement and extension of cell membrane

Question 8

what do intermediate filaments do?

Answer 8

form a network in the cell and are important in structural function

Question 9

what do microtubules to?

Answer 9

mportant in cell movement and division

Question 10

what are microtubules composed of?

Answer 10

alpha and beta tubulin subunits

Question 11

what is the ectoderm

Answer 11

germ layer that gives rise to the epithelia of the skin and its associated glands, and the oral, nasal and anal passages.

Question 12

what is the mesoderm?

Answer 12

germ layer that gives rise to the epithelial linings of the cardiovascular system and the mesothelium lining the peritoneal, pleural and pericardial cavities.

Question 13

what are the common features of epithelia? (4)

Answer 13

• all have basal lamina
• all non-vascular
• usually polarised
• bind together in sheets

Question 14

what do occluding junctions (tight junctions) do?

Answer 14

link cells to form a diffusion barrier

Question 15

what do anchoring junctions do?

Answer 15

provide mechanical strength

Question 16

what do adherent junctions do?

Answer 16

Link submembrane actin bundles of adjacent cells.

Question 17

what do desmosomes do?

Answer 17

Link submembrane intermediate filaments of adjacent cells

Question 18

what do communicating junctions do?

Answer 18

allow movement of molecules between cells.

Question 19

what is a junctional complex?

Answer 19

lose association of several types of junctions found in certain epithelial tissues

Question 20

what do gap junctions allow?

Answer 20

elective diffusion of molecules between adjacent

cells.

Question 21

what proteins produce pores in communicating junctions?

Answer 21

connexon

Question 22

what are the 4 classifications of covering epithelia?

Answer 22

1. cell shape
2. number of cell layers
3. cell surface or tissue surface specialisations
4. presence of specialised cell types

Question 23

what is the flattened cell shape classification?

Answer 23

squamous

Question 24

what is the cube shaped classification?

Answer 24

cuboidal

Question 25

what are the tall and thin shaped classification?

Answer 25

columnar

Question 26

what is the classification of a single layer?

Answer 26

simple

Question 27

what is the classification of two or more layers?

Answer 27

stratified

Question 28

what is the classification of tissue that appears to have multiple layers, but in fact all cells are
in contact with the basal lamina?

Answer 28

Pseudostratified

Question 29

what are surface specialisations?

Answer 29

• microvilli
• cilia
• keratinised

Question 30

what cells can be present in covering epithelia?

Answer 30

goblet cells

Question 31

what are microvilli?

Answer 31

Minute finger-like projections of the cell membrane that increase the surface area

Question 32

what are cilia?

Answer 32

Motile cell processes thats propel mucous or fluid over the cell surface.

Question 33

what are the microvilli found in the male reproductive tract?

Answer 33

stereocilia

Question 34

what is keratin?

Answer 34

group of tough structural proteins.

Question 35

what is epithelia classified as when it contains more than one type of classification?

Answer 35

transitional