Practical 2 - Epithelia Flashcards
What is the definition of an epithelium?
A cohesive sheet of cells with one or more layers, resting on a basement membrane.
What is the purpose of epithelia?
Form barriers for:
- protection
- absorption
- secretion
Simple vs stratified epithelia?
Simple - single layer of cells resting on a basement membrane.
Stratified - two or more layers of cells on a basement membrane.
What type is gall bladder epithelium?
Simple columnar epithelium
What type is oesophageal epithelium?
Stratified squamous non-keratinising epithelium.
Where is simple squamous epithelium found?
- blood vessel endothelium
- mesothelium (outside of lungs)
- peritoneum (outside of abdominal organs)
Where is simple cuboidal epithelium found?
Lines kidney tubules and small ducts.
Where is simple columnar epithelium found?
Lines stomach, intestines and uterus.
True or false: simple columnar epithelium can have cilia/microvilli?
True
What is the function of goblet cells in the small intestine?
Secrete mucin onto surface of epithelium as a lubricant.
How do cilia work? Where are they found?
Contain contractile proteins which enable them to beat rhythmically.
Respiratory tract & reproductive tract.
What are some features of stratified epithelium?
- protective
- many layers
- continually worn down and replaced by cells from below
Where is stratified epithelium found?
Sites subject to abrasive forces: skin, mouth, oesophagus, vagina, cervix.
How are cells replaced in stratified epithelium?
Immature cells rest against basement membrane. Cells are pushed up to the surface as they mature by new cells forming beneath them.
What is the function of keratin?
Keratin waterproofs the epithelium.