Final answer:
Glandular epithelia mainly comprise cuboidal epithelial cells that secrete glandular material and are found in gland ducts, as well as columnar epithelial cells, which include mucous-secreting goblet cells.
Step-by-step explanation:
Glandular Epithelial Cells
Glandular epithelia contain secretory cells that perform various functions such as secretion of mucous and enzymes. One of the primary types of epithelial cells found in glands is cuboidal epithelial cells. These are cube-shaped and possess a single, central nucleus, and they specialize in secreting glandular material. They are found lining the ducts of glands, such as in the kidney and liver, and are involved in secretion and absorption processes.
Another type of epithelial cell found in glands is the columnar epithelial cell, which is taller than it is wide and often contains goblet cells - unicellular glands that secrete mucus. Depending on their location, columnar cells may also feature microvilli for increased absorption surface or cilia for moving particles.