Simple cuboidal tissue is commonly located in which structures?

• A. Lung alveoli
• B. Kidney tubules and thyroid gland
• C. Intestinal goblet cells
• D. Cartilage

Answer: (B)

Simple cuboidal epithelium is a single layer of cube-shaped cells that lines ducts and tubules where secretion and absorption occur. It is commonly found lining kidney tubules and the follicles of the thyroid gland, where it forms the walls of small ducts and glands. In the lungs, the surfaces of the alveoli are lined by simple squamous epithelium, which is thin for efficient gas exchange, not cuboidal. The intestinal lining features simple columnar epithelium with mucus-secreting goblet cells, not a simple cuboidal layer. Cartilage is not epithelial tissue at all; it’s a connective tissue. So, kidney tubules and the thyroid gland are the typical structures with simple cuboidal epithelium.