EPITHELIAL TISSUE Description

1.     STRATIFIED CUBOIDAL EPITHELIAL TISSUE

Description: many layers of cuboidal cells with rounded central dark nuclei and are oriented at straight level in each level, the cytoplasm is evenly distributed and light in color. This tissue appears like well oriented blocks.

Location: secretory portion of many glands (sweat)

Function: protection and secretion

2.     STRATIFIED COLUMNAR EPITHELIAL TISSUE

Description: many layers of cylindrical cells with oval basal nuclei the bottom layers of cells are low in height while the cells of the apical layer have the highest cytoplasm.

Location: male urethra.

Function: protection and secretion.

3.     PSEUDOSTRATIFIED EPITHELIAL TISSUE

Description: appears to have more than one layer because of randomly lined cells and the nuclei at different levels. Each cell reaches the basement membrane so it is considered as simple type of epithelium. Usually the apical surfaces have cilia for movement. Some of them are modified to secrete mucous for lubrication.

Location: lining of the upper respiratory pathway.

Function: movement and secretion of mucous.

Slide #8: a section of mammal trachea stained with hematoxylin & eosin. The lining of the trachea represent the pseudostratified epithelium. Notice the oval nuclei in more than one level, the cilia, and the goblet cells.

4.     TRANSITIONAL EPITHELIAL TISSUE

Description: many layers (5-10) of dome shaped cells with rounded central and dark nuclei, the apical surface of the tissue is convoluted during the relaxed state which is the landmark feature of this tissue. In the stressed state the cells are compressed and flat with their small rounded nuclei.

Location: urinary bladder.

Function: protection and adaptation.

Slide #9: a section from urinary bladder stained with hematoxylin & eosin. The lining represents the transitional epithelium. Notice the multilayered cells and the dome like shaped cells on the apical layer.