L3: Epithelium Flashcards
What are the 4 basic functions of epithelium?
1) Physical protection
2) Permeability
3) Sensation
4) Contractibility/secretion
What are the 2 types of epithelium?
1) Covering epithelium
2) Glandular epithelium
What is the difference between simple and stratified?
Simple is only one cell layer thick
Stratified is 2+ cell layers thick
Describe the structure and function of simple squamous epithelial cells
- Thin, flat cells
- Looks like a fried egg when looked at from birds-eye view
- Very delicate
- Found where absorption and secretion take place
- Found in lungs
- Makes up membranes that lines body cavities
- Lines blood vessels
- Lines inside of heart
Describe the structure and function of simple cuboidal epithelial cells
- Looks like little boxes
- Hexagonal-shaped from birds-eye view
- Nucleus is round, found in centre. Occupies most of cell space
- Found where secretion/absorption occurs
- Found in ovaries
- Lines tubules in kidneys
- Found in thyroid
- Found in glands and ducts
Describe the structure and function of simple columnar epithelial cells
- Looks like columns
- Hexagonal in shape from birds-eye view
- Nucleus is elongated and found near base of the cell
- Provides a little bit of protection
- Found where secretion/absorption occur
- Lines stomach/intestines
Describe the structure and function of stratified squamous
- Organized in layers
- Cells closest to surface are flattened
- Found where stresses are present
- Makes up our skin
- Lines wet cavities of body (e.g., mouth)
Describe the structure and function of stratified cuboidal epithelial cells
- Not overly common in body
- Found in ducts and sweat glands (often in layers of 2)
Describe the structure and function of stratified columnar epithelial cells
- Not overly common in body
- Provides slight protection
- Found in throat/urethra
Describe the structure and function of transitional epithelial cells
- Multiple layers of cells
- Cells at basement membrane take variety of shapes
- Cells on surface are either domed shaped or cuboidal
- Found in bladder, ureter, parts of urethra
- Cells change shape depending on extension of body part (e.g., full bladder vs empty bladder)
Describe structure and function of pseudo-stratified columnar epithelial cells
- Nucleus looks like its in different places
- Looks stratified, but all do in fact touch the basement membrane
- Found in bronchi, trachea
- Often has cilia on its surface
Where would you find neuroepithelium?
- In the taste buds
- In olfactory cells
