Ch 4.1 Epithelial tissue Flashcards
Are epithelial tissues innervated? Are they vascularized?
Yes and No
What is directly underneath epithelial tissue? What is its role?
Epithelial tissue is supported by a layer of connective tissue directly underneath it.
What makes epithelial tissues polar?
Free apical surface and attached basal surface.
How are adjacent epithelial cells staying together?
Specialized cell junctions.
How are epithelial tissues classified?
Based on number of layers - simple and stratified.
Based on cell shape - squamous, cuboidal, columnar and transitional.
Describe simple squamous epithelium. Appearance, function and some locations.
- One layer of thin ‘squashed’ cell looking like a floor tiles.
- Their function is to allow diffusion of substances.
- Capillaries of blood vessels, alveoli in lungs.
Describe simple cuboidal epithelium. Appearance, function and some locations.
- Shape of a cube, single layered.
- Most often occurs in places where secretion plays big role.
- Ducts and glands in kidneys, liver etc.
Describe simple columnar epithelium. Appearance, function and some locations. What is the subtype?
- Single layer of cells aligned, of column shape.
- Its function is to absorb and secrete. Its thin enough to allow molecules to diffuse, but thick enough to have cell machinery responsible for process of molecular transport.
- Lines the stomach and intestines.
- One subtype of this cell is simple columnar epithelia bearing cilia (eyelashes). Cilia by moving rhythmically allow to move substances across certain body surfaces.
Describe pseudostratified columnar epithelium.
- ## Pseudostratified columnar cells vary in height, yet still all cells rest on basement membrane, only the tall cells however, reach the apical surface of the epithelium. Short cells differentiate over the time into tall ones. Their nuclei can be found at various levels giving a false impression of stratification.
