Epithelium Flashcards
Generally where does epithelial tissue exist?
- As a sheet of cells that covers a body surface or lines a body cavity.
- Occurs at the interface of two different environments
- Occurs in most of the body’s glands
How is epithelium classified?
- Number of layers
- Shape of cells involved
What are the two types of layers?
Simple (one layer)
Stratified (more than one layer)
What are the various types of shapes of cells involved?
- Squamous (flat cells)
- Cuboidal (cube like cells)
- Columnar (column like cells)
What type of epithelium is a single layer of tall cells that may have cilia and/or mucous secreting cells?
Simple Columnar Epithelium
What shape of cells has round oval-like nuclei?
Columnar cells
What type of epithelium has the function of absorption, secretion of mucous and enzymes, and when ciliated, propels mucous or reproductive cells?
Simple columnar
Where is simple columnar epithelium found in the non-ciliated type?
Found lining most of the digestive tract (stomach to anal canal), the gallbladder and excretory ducts of some glands
Where is the ciliated simple columnar located?
Found in the small bronchi, uterine tubes and some regions of the uterus
Explain the role of an endocrine gland.
They secrete substances directly into the bloodstream
Explain the role of an exocrine gland.
They are ducts that carry products onto epithelial body surfaces or into body cavities.
Examples include salivary glands and the liver/pancreas
What type of epithelial tissue is a single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm?
Simple Squamous
Which type of epithelial tissue functions to allow the passage of materials by diffusion/filtration in sites where protection is not important?
Simple Squamous
(also secretes lubricating substances in serosae)
Where is simple squamous epithelium located?
Found in
1. glomeruli of the kidney
2. air sacs of the lungs
3. lining of the heart (pericardial membrane) 4. blood vessels
5. lympathic vessels and the lining of ventral body cavities
What type of epithelial tissue is a single layer of cells that have large spherical central nuclei that forms to secrete and absorb?
Simple Cuboidal
Where is simple cuboidal epithelial found?
Located in the tubules of the kidneys, the ducts and secretory portions of small glands and is the surface of the ovary.
What type of epithelial tissue is technically a single layer that has cells of differing heights (meaning some do not reach free surfaces)
The nuclei of these cells are seen at different levels and some may contain cilia and goblet cells (secrete mucous)
Pseudo-stratified Columnar
What type of epithelium functions to secrete (particular mucous) and to propel mucous by ciliary action.
Pseudo-stratified columnar
Where is the non ciliated pseudo-stratified columnar epithelium located?
Found in the the male sperm carrying duct and the ducts of large glands.
Where is the ciliated pseudo-stratified columnar epithelium located?
Found in the lining of the trachea, and in most of the upper respiratory tract.
What type of epithelium is a thick membrane that is composed of several cell layers?
Stratified Squamous
Under the Stratified Squamous Epithelium is what layer of metabolically active cells?
The basal layer of cells is under and contains cuboidal and columnar cells
What is the function of stratified squamous epithelium?
It functions to protect the underlying tissue
Where is the non keratinized version of the stratified squamous epithelium located?
Forms the lining of the esophagus, mouth, and vagina
Where is the keratinized version of the stratified squamous epithelium located?
Forms the epidermis
What type of epithelium is generally seen as two layers of cube layers and functions to protect?
Stratified Cuboidal Epithelium
Where is stratified cuboidal epithelium found?
Found in the largest ducts of sweat glands, mammary glands and salivary glands.
What epithelial layer has several layers of cells that have large oval shaped nuclei and a basal layer that consists usually cuboidal cells?
Stratified columnar
What is the purpose of stratified columnar epithelium?
Protection and secretion
Where might you find stratified columnar epithelium?
Not found much in the body but has small amounts in the male urethra and in the large ducts of some glands.
What type of epithelium resembles both stratified squamous and stratified cuboidal?
Usually the basement cells are cuboidal or columnar and surface cells are dome shaped squamous-like
Transitional Epithelium
What is the purpose of transitional epithelium?
They stretch easily and allows the urinary organ to distend
Where is transitional epithelium located?
Lining of the ureters, bladder, and part of the urethra.
