W2 - Epithelial Cell Types Flashcards
What is the main functions for simple epithelium and why?
Selective diffusion because only on cell layer thick and on surface
Description of simple squamous cells
Flattened and irregular, forming a continuous surface
Diffusion and tissue fluid transport occurs across the simple squamous epithelium, where do these processes occur in the body respectively?
Lungs/capillaries and pleural/pericardial/peritoneal cavity linings
Why cannot the basement membrane be seen normally when staining the mesothelium with H+E? (simple squamous)
Has similar staining properties to collagen so cannot be distinguished
Description of simple columnar cells
Tall and polar due to positioning of elongated nuclei
Are the heights of columnar epithelial cells always the same?
No - it varies depending on site and function
What is the function of the small intestine and stomach linings where simple columnar cells are found?
Absorption in SI and secretion in stomach
In the endocervix lining, where are the nuclei typically positioned in the simple columnar cells?
They’re located basally
What is the function of nonciliated simple columnar cells (nucleus usually at base)?
Secretion
What do ciliated simple columnar cells (nucleus in middle) do in the female reproductive tract? (e.g. fallopian tubes)
Transports ovum from ovary to uterus
Around how many cilia can be present on one cell?
~300
Description of simple cuboidal cells
Square from side, polygonal from surface, circular and central nucleus
What do simple cuboidal cells typically line?
Excretory, secretory or absorptive small ducts + tubules
What does the nucleus of a simple cuboidal cell give a good estimation of?
Cell size (if can’t see boundaries clearly)
What colour does a BM stain when using an azan stain on a collecting tubule in the kidney?
Blue
Although simple pseudostratified columnar epithelium appear to have more than one cell layer, what characteristic means that it is definitely simple?
The fact that every cell rests on the basement membrane
Simple pseudostratified cells are usually polar, why?
Nuclei are disposed at varying levels but usually the basal 2/3rds of the cell
Are most cells in the simple pseudostratified columnar epithelium ciliated or nonciliated?
Ciliated
What is the difference between true stratified and pseudostratified cells? (polarity, layering and ciliation)
True - non polar, multilayered and nonciliated, Pseudo - polar, single layer and ciliated
Where can you find pseudostratified columnar epithelium?
In the respiratory epithelium in the bronchus
What is the main functions for stratified epithelium and why?
Protective function as multilayered so suited to dealing with abrasion
What may stratified epithelium be permeable to?
Water and small molecules
The stratified squamous epithelium that continuously matues from cuboidal base layer to flattened surface layer is in what layer of the skin?
Eepidermis
What two characteristics of stratified squamous tissue helps it to withstand abrasion?
Lots of cell junctions and keratin cytoskeleton
Give 3 examples of areas where stratified squamous epithelium is found
Vagina, oesophagus and oral cavity
What in the granular layer makes it waterproof?
Tight junctions
How many cell layers does stratified cuboidal epithelium have and where found (+function)?
2-3, endocrine glands in mammals (so excretory, protective and secretory)
Where is the only place stratified transitional epithelium is found?
Urinary tract
What are two characteristics or transitional epithelium that make it suitable to the urinary tract?
Very stretchy and can withstand toxicity of urine
What shapes are the basal, intermediate and surface layers of transitional epithelium?
Basal - cuboidal, intermediate - polygonal, surface - large and rounded (can have 2 nuclei)
What happens to the shape of the intermediate and surface cells in transitional epithelium when stretched?
Become very flat
