In addition to the tall columnar cells (CC) in this columnar epithelium, there is a definite layer of basal cells (BC). The columnar cells, which contain elongate nuclei and possess cilia (C), extend from the surface to the basement membrane (clearly visible in the trachea as a thick, acellular, homogeneous region that is part of the connective tissue (CT )). The basal cells are  interspersed
Pseudostratifed epithelium, epididymis, human, H&E ×450.
This is another example of pseudostratified columnar epithelium. Again, two layers of nuclei are evident, those of basal cells (BC) and those of columnar cells (CC). As in the previous example, however, although not evident, the columnar cells staining “goblet” (arrows) that contains the cell’s  secretory product. The epithelium lines the lumen of the colon and extends down into the connective tissue to form the intestinal glands (GL). Both cell types are tall with their nuclei located at the base of the cell. The connective tissue (CT) contains numerous cells, many of which are lymphocytes and plasma cells.
between the columnar cells. Because all of the cells rest on the basement membrane, they are regarded as a single layer, as opposed to two discrete layers, one over the other. Because the epithelium appears to be stratified but is not, it is called pseudostratified columnar epithelium. The circle in the micrograph delineates a tracheal gland similar to the acinus in exocrine pancreas (circle). Note that the lumen of the gland is clearly visible and the cell boundaries are also evident. The gland epithelium is simple columnar.
rest on the basement membrane; thus, the epithelium is pseudostratified. Note that where the epithelium is vertically oriented, on the right of the micrograph, there appear to be more nuclei, and the epithelium is thicker. This is a result of a tangential plane of section. As a rule, always examine the thinnest area of an epithelium to visualize its true organization.
Stratifed squamous epithelium, vagina, human, small, with little cytoplasm, and thus the nuclei appear closely packed. As H&E ×225. the cells become larger, they tend to flatten out, forming disc-like squames. Because the surface cells retain this shape, the epithelium is
This is the stratified squamous epithelium of the vaginal called stratified squamous.
wall. The deeper cells, particularly those of the basal layer, are
KEY BC, basal cell C, cilia CC, columnar cell CT, connective tissue GL, intestinal gland arrows: upper left, duct composed of simple squamous epithelium; upper right, lateral boundaries of cuboidal tubule cells; middle left, mucus cups of goblet cells asterisk, duct or tubule of simple cuboidal epithelium
Tissues that resemble epithelia but lack the characteristic free surface are designated epithelioid tissues. This is the characteristic structure of the endocrine organs, which develop from typical epithelia but lose their connection to a surface during development.
Stratifed epithelia, esophagus, monkey, H&E ×250.
This part of the wall of the esophagus reveals two different epithelia. On the left is the lining epithelium of the esophagus. It is multilayered with squamous surface cells; therefore, it is a stratified squamous epithelium (SS). On the right is the duct of an esophageal gland cut in several planes. By examining a region where the plane of section is at a right angle to the surface, the true character of the epithelium becomes apparent. In this case, the epithelium consists of two cell layers with cuboidal surface cells; thus, it is stratified cuboidal epithelium (StCu).