Tissue Organisation - Epithelial tissue Flashcards
What are the 4 types of simple epithelia?
Simple squamous
Simple cuboidal
Simple columnar
Pseudostratified
What is the definition of a tissue?
A group of cells that have a similar structure and function - a collection of cells and their surrounding structures.
What is the definition of an organ?
Mixture of the 4 basic tissue cells to perform one or more function.
What are the 4 types of tissue?
Epithelia
Connective
Nerve
Muscular
What is the function of the epithelia?
Protection
Absorption
Secretion
How do epithelia receive nutrients/oxygen and why?
Through diffusion from adjacent connecting tissue because it’s avascular (doesn’t have its own supply)
How is epithelia classified?
Shape
Number of cells
What is simple squamous?
A single layer of flattened cells
What is simple cuboidal?
a single layer of cuboidal (cube-like) cells which have large, spherical and central nucleus
What is the structure of all epithelial cells?
All epithelial cells are attached on their basal surface to a basement membrane
Where can simple squamous epithelial cells be found?
Lining blood vessels
Where can simple cuboidal epithelial cells be found?
in ducts e.g. kidneys where they perform secretion and absorption
What is simple columnar?
a single layer of cells that are taller than they are wide
Where can simple columnar epithelial cells be found?
- lining of the intestine where it absorbs nutrients from the lumen
- stomach where it secretes acid, digestive enzymes and mucous.
What is pseudostratified?
Same arrangement as simple columnar BUT the nuclei have random arrangement (not fixed to the centre)
Where can you find pseudostratified epithelial cells?
In the trachea/upper respiratory tract
Order these:
Basement membrane Apical side Connective tissue Epithelial cells Basal side
Apical side > epithelial cells > basement membrane > connective tissue > basal side
What are stratified epithelial cells?
Epithelia made up of more than one layer or cells
What are the 5 types of stratified epithelia?
Stratified squamous Keratinized stratified squamous Stratified columnar Stratified cuboidal Transitional
What are keritinized stratfied squamous cells?
Have a layer of dead squamous cells at the top and keratin deposited on the surface which makes it impermeable/waterproof and dry - reduces evaporation
What are transitional epithelial cells?
Cells that change shape - depends on bladder
When bladder full, cells expand = squamous shape
When bladder empty, cells deflate = cuboidal shape
Where are the 5 types of stratified epithelial cells found?
Stratified squamous - mouth and vagina Keratinized stratified squamous - skin Stratified columnar - male uretha Stratified cuboidal - glands Transitional - lines bladder and uretha
