Epithelial cells Flashcards
What are contractile tissues?
Skeletal muscles, cardiac muscles, smooth muscles
What are carcinomas?
Epithelial cancer
What are sarcomas?
Mesenchymal cancers ( connective and muscle tissue )
What are gliomas?
Glial cell cancers
Why are epithelial cells not leaky?
Organised stable cell-cell junctions for continuous cohesive layers
How are epithelial cells classified?
Shape and layering
Where are single squamous epithelium found?
Lung alveolar
Mesothelium
Endothelium linings
Allow gas exchange
Where are simple cuboidal epithelium found?
Linings found in ducts e.g. kidney
Where are simple columnar epithelium found?
Enterocytes lining the gut - up take nnd breakdown of products of digestion
What two types of stratified squamous epithelium are there?
Keratinising
Non-keratinising - mouth lining, anus, oesophagus, cervix, vagina
Why are Keratinising stratified squamous stronger and used for epidermis.
The epithelium produces keratin and die in the process becoming thicker. Strong protective structures.
- Lose cellular organalles - cannot see under microscope
What is Pseudo-stratified epithelium?
Appears multi layered
But have contact with the basal lamina
Airways, urinary and reproductive ducts
What is the apical domain?
The area of the epithelial cell membrane at the lumenal surface
What is the basolateral domain?
The area of the epithelial cell membrane in contact with the extracellular matrix
What is the membrane between the apical and basolateral domain called?
Lateral membrane
What is epithelial polarity and why is it needed?
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.
What would happen if epithelial cell polarity is compromised?
Would secrete both ways = fatal. E.g. secreting digestive enzymes towards basal membrane could digest own system.
What do cell-cell junctions occur between epithelia?
Tight junctions : Seal gaps
Adherens junction : Control formation of junctions
Desmosomes : Join tough junction
Gap junction : To exchange material
What are the adaptations of transporting epithelial?
High concentration of ion transporters
Mitochondria in between Basal in-foldings
Increasing membrane to pump ions and water
How are Secretory Epithelium adapted for their function?
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
What is Constitutive secretion?
Secretory vesicles form and move directly to membrane to release content
What is stimulated secretion?
Secretory vesicles stored in cytoplasm and fuse when stimulated
What are two examples of epithelial proliferation?
Cells in intestinal crypts replacing cells lost from villi tips
cells of basal layer on stratified squamous diving to replace cells lost from surface
Why are gastro intestinal disturbances side effects of chemotherpay?
Inhibition of proliferation of intestinal crypt cells = flattening of intestinal villi
- Inhibited by 5-FU
What can Papilloma virus cause?
Hyperproliferation increasing surface growth by taking over stratified squamous epithelia
- warts and corns are also caused by hyperproliferation
