Simple cuboidal epithelium is a type of epithelial tissue consisting of a single layer of cube-shaped cells, each with a large, centrally located spherical nucleus. These cells are roughly as tall as they are wide and are tightly packed with minimal space between them. This epithelium is found lining secretory ducts and tubules in organs such as the kidney tubules, glands (e.g., thyroid, salivary glands), and parts of the respiratory tract like the bronchioles. Its main functions include secretion, absorption, and protection, with some variations depending on its location in the body. For instance, in the kidneys, it helps in filtration and absorption, while in glands, it aids secretion. Some cells may have specialized structures like cilia or microvilli to assist in their roles.