Epithelial cells

Question 1

What are contractile tissues?

Answer 1

Skeletal muscles, cardiac muscles, smooth muscles

Question 2

What are carcinomas?

Answer 2

Epithelial cancer

Question 3

What are sarcomas?

Answer 3

Mesenchymal cancers ( connective and muscle tissue )

Question 4

What are gliomas?

Answer 4

Glial cell cancers

Question 5

Why are epithelial cells not leaky?

Answer 5

Organised stable cell-cell junctions for continuous cohesive layers

Question 6

How are epithelial cells classified?

Answer 6

Shape and layering

Question 7

Where are single squamous epithelium found?

Answer 7

Lung alveolar
Mesothelium
Endothelium linings

Allow gas exchange

Question 8

Where are simple cuboidal epithelium found?

Answer 8

Linings found in ducts e.g. kidney

Question 9

Where are simple columnar epithelium found?

Answer 9

Enterocytes lining the gut - up take nnd breakdown of products of digestion

Question 10

What two types of stratified squamous epithelium are there?

Answer 10

Keratinising

Non-keratinising - mouth lining, anus, oesophagus, cervix, vagina

Question 11

Why are Keratinising stratified squamous stronger and used for epidermis.

Answer 11

The epithelium produces keratin and die in the process becoming thicker. Strong protective structures.

• Lose cellular organalles - cannot see under microscope

Question 12

What is Pseudo-stratified epithelium?

Answer 12

Appears multi layered

But have contact with the basal lamina

Airways, urinary and reproductive ducts

Question 13

What is the apical domain?

Answer 13

The area of the epithelial cell membrane at the lumenal surface

Question 14

What is the basolateral domain?

Answer 14

The area of the epithelial cell membrane in contact with the extracellular matrix

Question 15

What is the membrane between the apical and basolateral domain called?

Answer 15

Lateral membrane

Question 16

What is epithelial polarity and why is it needed?

Answer 16

Different regions of the cell surface being different from one another with discretely organised cellular structures

Required to give directionality eg. secretions in one direction.

Question 17

What would happen if epithelial cell polarity is compromised?

Answer 17

Would secrete both ways = fatal. E.g. secreting digestive enzymes towards basal membrane could digest own system.

Question 18

What do cell-cell junctions occur between epithelia?

Answer 18

Tight junctions : Seal gaps

Adherens junction : Control formation of junctions

Desmosomes : Join tough junction

Gap junction : To exchange material

Question 19

What are the adaptations of transporting epithelial?

Answer 19

High concentration of ion transporters
Mitochondria in between Basal in-foldings
Increasing membrane to pump ions and water

Question 20

How are Secretory Epithelium adapted for their function?

Answer 20

Arranged in tubules and glands

Can be exocrine or endocrine

Have extensive rough ER in the basal cytoplasm near basal lamina. And secretory granules in the apical cytoplasm

Question 21

What is Constitutive secretion?

Answer 21

Secretory vesicles form and move directly to membrane to release content

Question 22

What is stimulated secretion?

Answer 22

Secretory vesicles stored in cytoplasm and fuse when stimulated

Question 23

What are two examples of epithelial proliferation?

Answer 23

Cells in intestinal crypts replacing cells lost from villi tips

cells of basal layer on stratified squamous diving to replace cells lost from surface

Question 24

Why are gastro intestinal disturbances side effects of chemotherpay?

Answer 24

Inhibition of proliferation of intestinal crypt cells = flattening of intestinal villi

• Inhibited by 5-FU

Question 25

What can Papilloma virus cause?

Answer 25

Hyperproliferation increasing surface growth by taking over stratified squamous epithelia

• warts and corns are also caused by hyperproliferation