Epithelial biology

Question 1

what is epithelium?

Answer 1

protective layer of closely packed cells that don’t let things in and out

Question 2

look at this epithelial cell structure
what do hemidesmosomes do?

Answer 2

connect epithelial cells to basal lamina

Question 3

look at this epithelial cell structure
what do desmosomes do?

Answer 3

connect epithelial cells together

Question 4

what are the classifications of epithelium?

Answer 4

one layer: simple or pseudostratified
two or more layers: stratified

Question 5

what are the classifications of epithelial cells?

Answer 5

Flattened: squamous
Cubes: cuboidal
Columns: columnar

Question 6

what type of epithelium is oral mucosa?

Answer 6

is stratified squamous epithelial cells

Question 7

describe the Formation and maintenance of keratinised layer of epithelium

Answer 7

Cells proliferate and move away towards the outer area where they stop proliferating and start differentiating having lots of proteins.

Question 8

what is cell proliferation?

Answer 8

an increase in the number of cells; a result of cell growth and cell division.

Question 9

what happens in G0 of the cell cycle?

Answer 9

rest: cells metabolically active but no signals to divide

Question 10

what happens in G1 of the cell cycle

Answer 10

cellular contents except chromosomes are replicated
restriction point that stops cells going into S phase due to lack of extracellular signals
cyclin-dependant kinases and cyclins interact with each other to allow the cell to go through cell division

Question 11

what allows the cell to go through cell division in the G1 phase of the cell cycle?

Answer 11

cyclin-dependant kinases and cyclins interact with each other

Question 12

what happens in the S phase of the cell cycle?

Answer 12

DNA and chromosomes replicated

Question 13

what happens in the G2 phase of the cell cycle?

Answer 13

cells check that everything has been replicated correctly

Question 14

what happens during the mitosis phase of the cell cycle?

Answer 14

two nuclei and cells split in two - cytokinesis

Question 15

what controls proliferation?

Answer 15

Signals come via receptors in basal layer cells, via extracellular matrix through phosphorylation

Question 16

what do growth factors do?

Answer 16

controls cell growth and differentiation. Localised

Question 17

what do transcription factors do?

Answer 17

protein that regulates the activity of RNA polymerase

Question 18

describe the cell proliferator unit

Answer 18

• Progenitor cells are in basal layer
  Dividing cells appear in clusters

Question 19

what are the two types of cell proliferator unit?

Answer 19

Slow dividing but always have proliferative potential
Faster dividing but limited number of divisions

Question 20

There are certain cells in the basal layer that have potential to be stem cells. what are stem cells?

Answer 20

• Divide without limit
  When divides each daughter cell has choice as to what it differentiates into

Question 21

what is differentiation?

Answer 21

process by which cells or tissues undergo change toward a more specialised form or function
Change in gene expression

Question 22

what is one of the major reasons why a cell stops dividing?

Answer 22

removal of alpha 6 beta 4 - laminin as this attaches the hemidesmosome to the basal lamina. So cells move away from the basal lamina and start to differentiate

Question 23

what is the cytoskeleton?

Answer 23

system of protein filaments in the cytoplasm that gives the cell shape and movement of organelles in the cell itself

Question 24

what are the most abundant components of the cytoskeleton?

Answer 24

actin
intermediate filaments
tubulin

Question 25

what does tubulin do in the cytoskeleton?

Answer 25

move organelles and cytokinesis

Question 26

what does actin do in the cytoskeleton?

Answer 26

support and enable cells to move, muscle cell contraction

Question 27

what does intermediate filaments do in the cytoskeleton?

Answer 27

span the epithelium from one cell-cell junction to another strengthening the entire epithelium

Question 28

describe the structure of an epithelial intermediate filament

Answer 28

Rope like structure as one type I and one type II keratin intermediate filament intertwined

Question 29

how is a keratin divided into type I or type I?

Answer 29

if its an acid or base
Type I: Keratins 9-20
Type II: Keratins 1-8

Question 30

Type I keratins are found on what chromosome?

Answer 30

17q

Question 31

type II keratins are found on what chromosome?

Answer 31

12q

Question 32

oral epithelium has two types of keratinisation, what are they?

Answer 32

keratinised and non-keratinised

Question 33

in keratinised oral epithelium what keratins are found in the basal layer?

Answer 33

K5 and K14

Question 34

in keratinised oral epithelium what keratins are found in the outer layers?

Answer 34

k1 and K10

Question 35

in non-keratinised oral epithelium what keratins are found in the basal layer?

Answer 35

K5 and K14

Question 36

in non-keratinised oral epithelium what keratins are found in the superficial layer?

Answer 36

K4 and K13