1 Epithelial Tissues Flashcards
Explain the position, structure and function of the basement membrane.
The basment membrane (lamina propria) is located just under the epithelium. It is used for support, for epithelial cells to adhere into and a molecular and cellular filter. It is an acellular layer composed of the basal lamina which is laid down by the epithelial cells.
Define epithelia exactly.
A sheet of contiguous cells, of varied embryonic origin, that cover the external surface of the body and line internal surfaces.
Describe the ways in which epithelia are classified, explaining what is meant by the classification terminology, simple, stratisfied/compound, pseudostratisfied, squamous, cuboidal, columnar.
Simple - one cell thick Stratified - multiple cells thick Squamous- squashed thin cells Cuboidal - squarish block shaped cells Columnar - long thin cells Pseudostratified - appear to be stratified (nuclei at serval locations) but really simple.
Explain the reasons for the different rates of renewal of each type of epithelium.
Rates of renewal greatly depend on location and function. The rates remain constant unless there is injury. The skin for example is 28days, it is keratinised so hard to damage however the gut wall is every 6 days as it is in a harsh acidic environment.
