Final answer:
Epithelial tissues are found on body surfaces and internal organs, characterized by cellularity, special junctions, polarity, and a basal lamina. They are classified based on cell shape (squamous, cuboidal, columnar) and cell layering (simple, stratified, pseudostratified, transitional).
Step-by-step explanation:
Characteristics and Classification of Epithelial Tissue
Epithelial tissues are found covering the surface of the body, lining the cavities and tubes, and covering internal organs. They exhibit several key characteristics:
- Highly cellular with minimal extracellular material
- Specialized cell junctions including tight junctions, anchoring junctions, and gap junctions
- Cell polarity with distinct structural and functional differences between the apical and basal surfaces of the cells
- A basal lamina that provides attachment to the underlying connective tissue
Epithelia are classified based on cell shape and the number of cell layers. The shapes can be:
- Squamous (flattened and thin)
- Cuboidal (boxy)
- Columnar (rectangular)
Depending on the layers, epithelia can be:
- Simple epithelia (single layer)
- Stratified epithelia (multiple layers)
- Pseudostratified (appears as multiple layers but is actually one)
- Transitional (shape of cells can vary)