Epithelia Flashcards
How many cell layers do simple epithelia have?
A single layer of cells
How many cell layers do stratified epithelia have?
Many layers of cells
Appearance of simple squamous
Thin scales
Specialisation of simple squamous
Facilitated rapid passage of molecules
Appearance of simple cuboidal
Fat cells with nuclei in the middle of the cells
Function of simple cuboidal
Secretion and absorption of molecules via active transport
Appearance of simple columnar
With cilia (on apical side) or without cilia
Longer cells with nuclei at lower
Function of simple columnar
Absorption/secretion of molecules via active transport
Removal of respiratory particle matter
Line fallopian tubes
Appearance of pseudostratified columnar
Single cell layer with multilayer appearance
Nuclei reside at different levels
Ciliated cells interspersed with goblet cells
Basal membrane
Appearance of stratified squamous
Apical = squamous
Basal = cuboidal/columnar
Where do stratified squamous cells reside?
In areas of high abrasion
Keratinised in skin upper layers
Non keratinised in oesophagus
Appearance of stratified cuboidal
Nuclei present fat
Where do stratified cuboidal cells reside?
In glands
Function of stratified columnar
Allow tissues to stretch or contract
Where do stratified columnar cells reside?
Conjunctiva, pharynx, anus, male urethra and embryo
Appearance of transitional cells
Cells are round when relaxed
Flat when contracted
Function of transitional cells
Facilitates shape change in distension without damaging epithelial lining
Where are mucus secretions produced?
Mucus gland
Where are protein secretions produced?
Serous gland
Where are ductless secretions produced for?
The endocrine system
Where are duct secretions produced for?
The exocrine system
What cells are unicellular secretions released from?
Goblet cells
What cells are multicellular secretions released from?
Acinar/acinus cells
What is the function of the basement membrane?
Separates the epithelia from underlying connective tissue
Provides mechanical strength
What is the basal lamina spilt into?
Lucida and Densa
Where does the reticular lamina reside?
Under the basal lamina
Fibres anchor the basal lamina to collagen or elastin
How to lateral cell to cell communications occur?
Via Gap junctions
What filament allows for contraction?
Myosin filaments
What is linked by adhesion junctions?
Stress bearing cytoskeleton links cells to cell via adhesion junctions
How long does interstial self-renewal take?
5 days
How long does the interfollicular epidermis take ?
4 weeks
How long does renewal of lung epithelium take?
up to 6 months
What does adherens junction connect?
Actin filament bundles in 1 cell to the next
What do desmosomes connect?
Intermediate filaments (cells with high mechanical stress)
What do hemidesmosomes connect?
Anchors intermediate filaments to extracellular matrix
What do tight junctions connect?
Seals the gap between epithelial cells on apical surface
What do tight junctions connect?
Seals the gap between epithelial cells on apical surface
What induces formation of epithelium?
Switched expression of cadherins inducing mesenchymal cells (fibroblasts) to form epithelium
