This document summarizes the key characteristics of epithelial tissue. It notes that epithelial tissue is avascular and made up of sheets of cells with little intercellular material. Epithelial tissue can be simple with one cell layer, or stratified with two or more layers. The shape and arrangement of cells and nuclei define different types of epithelia like squamous, cuboidal, columnar, and pseudostratified. Epithelial tissue has functions like protection, absorption, secretion, and sensation.

1. EPITHELIAL
TISSUE

2. • an avascular basic tissue made up of aggregates
of cells organized in continuous sheets with very
minimal amount or no intercellular material in
the extracellular space
• covers many of the body's free surface, lines
internal closed cavities and body tubes as well as
secretory portions of glands and ducts

3. • shape of the cell present
• squamous - flat, plate-like cells
• cuboidal - cells with similar height and distance
• columnar - taller than wide
• number of cell layers
• simple - one layer of cells
• stratified - 2 or more layers
classified based on the following:

5. an epthelial membrane that is
made up of one layer of cells is
called?

6. simple epithelia

7. an epthelial membrane
containing more than one layer?

8. stratified or complex
epithelia

9. an epthelium that appears
stratified because the nuclei is
found at different levels ?

10. pseudostratified epithelium

12. • protection
• reduction of friction
• absorption
• secretion
• excretion
• synthesis of various proteins
• sensory capacity
epithelial tissue posses numerous functions:

13. • nucleus of each cell appears flattened and the
cytoplasm is indistinct
• further divided into
• mesothelium
• endothelium
• flattened cell epithelium
simple squamous epithelium

14. • height, width, depth are the same
• round, centrally placed nucleus
simple cuboidal epithelium
simple columnar epithelium
• height is 2-3 times greater than their width
• nuclei: less oval, basally located and arranged
uniformly at the same level

16. • conves an impression that it is stratified
• pseudo - false ; stratified - many layers
• upon close examination, it demonstrates a layer
of closely packed cells of varying height and
girth
• nuclei are found at different levels
pseudostratified epithelium

18. • two or more layers
• durable and can protect underlying tissue, thus
can be seen in areas where there is considerable
wear and tear
• SUBTYPES
• stratified squamous
• stratified cuboidal
• stratified columnar
stratified/complex epithelium

19. • special type of stratified epithelium
• made up of several layers of cells that become
flattened when stretched
• lines the organs subjected to contraction and
stretching e.g., urinary bladder
transitional epithelium