Flashcards in Organisation of epithelial cells Deck (12):
What type of epithelium does the small intestine have?
absorptive epithelium with goblet cells
What is a gland?
Tubular structure with secretory role - known as crypts in intestine
What are the types of glands?
Simple tubular – e.g. crypts; single closed tube
Compound – branched
Acina/alveolar – secretory cells restricted to regions with a specialised rounded shape at the ends of the
What is the mesentery
tissue attaching intestine to rest of the body - allows intestine to be folded to be contained in the abdominal cavity but still have blood and nerve supply
What is the epithelium type of the mesentery?
simple squamous (same as endothelium)
why is the oesophagus epithelium stratified?
The stratified arrangement means that if the cells adjacent to the lumen become damaged, the cells underneath maintain the function of the epithelium as a barrier and can divide to replace those that are lost.
What does trachea epithelium do?
Separates the lumen from the surrounding body tissue, including rings of cartilage which hold the airway open
What kind of epithelium does the trachea have?
Pseudo-stratified columnar ciliated epithelium
Cell renewal in epithelia
- The cells in a pseudo-stratified epithelium which do not extend all the way to the luminal surface provide a specialised population of dividing cells, known as stem cells.
- In the small intestine stem cells are located within the crypts.
- In stratified epithelia the dividing stem cells are present in the basal layer adjacent to the basal lamina.
- In all three cases the dividing cells are located where they have minimum susceptibility to damage.
- A different strategy is found in some other epithelia, including simple squamous and the simple cuboidal epithelia of many ducts. Here all of the cells are capable of cell division when required.
What is the importance of stratified squamous epithelium?
Type of epithelium in skin?
The body uses a stratified squamous epithelium in several locations as a protective strategy, with the skin being a special case. Skin has to be waterproof to prevent the cells below drying out and dying. The surface cells of the epithelium have died leaving only the dense network of their keratin
- The epithelium of the skin is the epidermis. This is a stratified squamous epithelium..