Histology of epithelium Flashcards
Name components A-I in this diagram
What is the role of the capillary/blood vessel in the connective tissue?
diffusion of nutrients from underlying connective tissue layer
Why do we need junctional complexes between epithelial cells?
there is little intercellular substances, require gap junctions for cell to cell communication
Where do epithelial cell need to stick to?
adjacent cells and the basement membrane
What is the apical and basal side of the epithelium?
apical (surface)
basal (basement)
What are the 3 junctions located in the epithelium, communicating 2 epithelial cells?
tight junctions
adherens junctions
gap junctions
What is the intermediate filaments connecting epithelial cells together?
desmosome
What is the intermediate filament connecting the epithelial cells to the basal lamina?
hemidesmosome
What is this an example of?
tight junction
What is this an example of?
adherens junction
What is this an example of?
gap junction
What is this an example of?
hemidesmosome and desmosome
What are the 2 basic classifications of epithelium based on number of layers?
Simple - 1 layer
Stratified - made of many layers
What are the different cell shapes?
squamous
cuboidal
columnar
Name cell shapes is A-C
Classify epitheliums A-D
What is the structure of squamous epithelium?
single layer of flattened cells
What is the function of simple squamous epithelium?
ideal where diffusion/filtration are needed
No protective function
Where is the simple squamous epithelium located?
- Inner lining of the heart and vascular tubes
-Lining of body cavities (serous layer – pleura, pericardium, peritoneum) - Kidney glomeruli
What is the structure of the simple cuboidal epithelium?
- Single layer of cube like cells
- Round central nucleus
What epithelium classification is shown?
simple cuboidal epithelium
What is the function of the simple cuboidal epithelium?
secretion
absorption
Where is the simple cuboidal epithelium located?
Kidney tubules
Small glands– secretory portion and ducts
What epithelium is this and what is the arrow pointing to?
Collecting tubule of kidney showing simple cuboidal epithelium
What epithelium classification is shown in by the arrows?
simple columnar epithelium
What is the structure of the simple columnar epithelium?
- Tall cells in single layer
- Free surface may have surface modifications – microvilli, cilia
What is the function of the simple columnar epithelium?
Secretion
Absorption
Propelling mucus
Where is the simple columnar epithelium located?
Non-ciliated variety:
Digestive tract
Ducts of large glands
What is arrows at ‘A’ pointing to?
What classification of epithelium do these images show?
Pseudostratified (ciliated) epithelium in respiratory passages
pseudostratified epithelium
What is the structure f the pseudostratified epithelium?
- Single layer of columnar cells of different heights
- Gives false appearance of more than 1 layer of cells
- Is always ciliated
What is the function of the pseudostratified epithelium?
Propulsion of mucus
Secretion of mucus
Helps in clearing surface of debris
Where is the pseudostratified epithelium located?
Respiratory conducting passages ie. from trachea all the way down to respiratory bronchioles
What epithelial classification does the image show?
stratified squamous epithelium
SKIN- KERATINISED
What are the 2 types of stratified squamous epithelium?
keratinised and non-keratinised
What is the epithelium classification shown here?
stratified squamous epithelium
OESOPHAGUS - NOKERATINISED
What is the structure of the stratified squamous epithelium?
- Multiple layer of cells
- Basal layer cuboidal/columnar lies on basement membrane, metabolically active.
- Cells on surface flattened
- May be dead cells (keratinised epithelium)
What is the function of the stratified squamous epithelium?
Protection from abrasion, dessication, waterproofing
Where is stratified squamous epithelium locacted?
- Skin (keratinised)
- Oesophagus (nonkeratinized)
- Lining of vagina (nonkeratinized)
