Epithelial Cells and Tissues

Question 1

What is the breakdown of the formation of an organism?

Answer 1

Group of cells -> Tissues
Group of Tissues->Organ
Group of organs _> organ systems
Group of organ systems-> organism

Question 2

What are tissues?

Answer 2

Groups of cellls whose type, organisation and architecture is integral to its function

made up of cells, extracellular matrix and fluid

Question 3

What is the ECM?

Answer 3

material deposited by cells which forms the insoluble part of the extracellular environment

Question 4

What is ECM generally composed of?

Answer 4

fibrillar (or reticular) proteins such as, collagens or elastin, embedded in a hydrated gel with proteoglycans or/+ ground substance)

Question 5

Organisation of ecm?

Answer 5

depends on where : poorly in places such as loose connective tissue or highly in bone, tendon and basal lamina

Question 6

What are the main cell types?

Answer 6

HECCN:
Haematopoietic cells
Epithelial Cells
Contractile tissues
Connective tissue cells
Neural cells

Question 7

What are connective tissue cells?

Answer 7

cells such as fibroblasts found in many tissues

Chondrocytes - cells that make cartilage and osteocytes - make bone

Question 8

What are contractile tissues?

Answer 8

skeletal muscle, cardiac muscle, smooth muscle

Question 9

What are haematopoietic cells?

Answer 9

blood cells, tissue resident immune cells and cells of bone marrow from which they are derived

Question 10

What are neural cells?

Answer 10

cells of nervous system:
Neurones that carry electrical charge
glial cells = support cells

Question 11

What are epithelial cells?

Answer 11

cells forming continuous layers within organs. line various surfaces and separate tissue compartments and have a variety of other functions

Question 12

Cancers of epithelial tissues are called what?

Answer 12

carcinomas

Question 13

what is a sarcoma?

Answer 13

cancer of connective tissue and muscle

Question 14

What are leukaemias or lymphomas?

Answer 14

haematopoietic cancers
from bone marrow cells
lymphocytes

Question 15

What are neural cell cancers called?

Answer 15

Neuroblastomas from neurones or gliomas from glial cells

Question 16

How are epithelial cells organised?

Answer 16

They make organised, stable cell junctions to form continuous, cohesive layers

cell to cell junction = imp in forming and maintaining layers

Question 17

What are ep cells really important for?

Answer 17

lining internal and external surfaces

and
transport, absorption e.g. enterocytes have specialised ep cells for this, secretion, protection

Question 18

What are the two main criteria of epithelial cell classification?

Answer 18

shape and layering

Question 19

What are the varieties of shapes?

Answer 19

squamous
cuboidal
columnar - column like

Question 20

What are the varieties of layers in epithelial cells?

Answer 20

Single layer = simple epithelium

Many layers = stratified

Question 21

What is squamous?

Answer 21

shape characterisation: (flattened plate-shape)

Question 22

What is columnar?

Answer 22

Arranged in columns (shape)

Question 23

What is cuboidal?

Answer 23

cube like - shape

Question 24

Where is simple squamous epithelium found?

Answer 24

lung alveolar (Air sac) epithelium, 
mesothelium (lining major body cavities)
endothelium (lining bv and other blood spaces)

Question 25

what does the thin epithelium formed by a simple squamous layer allow?

Answer 25

exchange, e.g. gas exchange in alveoli

Question 26

Where are simple cuboidal epithelium found?

Answer 26

typical linings found in duct e.g. lining kidney collecting duct

Question 27

What are the simple columnar ep cells typically found in/on?

Answer 27

surfaces involved in the absorption and secretion of molecules

also much more elongated

Question 28

What are the two types of stratified squamous epithelium?

Answer 28

Keratinizing

non-keratinizing

Question 29

What are keratinizing epithelium?

Answer 29

1 of the stratified squamous type:
epithelial cells which prod keratin and in doing die becoming thicker, stronger, protective structures e.g. epidermis - skin epitheium.

they lose their cellular organelles and nuclei, which are not visible under light microscopy

Question 30

What are non-keratinizing epithelium?

Answer 30

ep cells that do not undergo keratinisation. retain nuclei and organelles e.g. epithelium lining mouth, cervix, anus, oesophagus, vagina

Question 31

are all the cells in stratified squamous epithelium the same?

Answer 31

no, cell shapes vary in the various layers. the squamous is only related to the surface of the cell

Question 32

Why is keratinising epithelium beneficial?

Answer 32

can form thick layers that protect underlying tissues from various things such as heat, cold, solvents (alcohols), abrasion etc. (phys and chem)

Question 33

what are pseudo-stratified epithelium cells?

Answer 33

appear to be multi layered but are single. on close examination the surface cells have contact with the basal lamina.

pseudo means fake

Question 34

Where are pseudostratified epithelium found?

Answer 34

airway - epithelium of trachea and bronchi, various ducts in urinary and reproductive tracts

Question 35

What is an epithelial cell membrane organised into?

Answer 35

domains: apical and basolateral

Question 36

Are epithelial functions random or not?

Answer 36

most are directional so are highly organised and NOT random e.g. secretion, fluid and solute transport and absorption

Question 37

What is required for directionality needed for epithelial function?

Answer 37

epithelial polarity which is seen as different regions of the cell surface being different from one another with discretely organised cellular contents

Question 38

Where is the apical domain?

Answer 38

apical at lumenal (open) surface / above junction

Question 39

Where is basolateral domain?

Answer 39

basolateral everything below junction
basal surface is in contact w the ecm
lateral membrane is what opposes the adjacent cell