Simple columnar epithelium – is a single layer of columnar epithelial cells which are tall and slender with oval-shaped nuclei located in the basal region, attached to the basement membrane. In humans, simple columnar epithelium lines most organs of the digestive tract including the stomach, and intestines. Ciliated columnar epithelium has many cilia which moves mucus and other substances via mucociliary clearance in the respiratory tract. It is present in the lining of the fallopian tubes, where currents generated by the cilia propel the egg cell toward the uterus. Ciliated columnar epithelium – forms the neuroepithelium of the ependyma that lines the ventricles of the brain and central canal of the spinal cord. These cilia move the cerebro-spinal fluid (CSF). Simple cuboidal epithelium – consists of a single layer cells that are as tall as they are wide. The important functions of the simple cuboidal epithelium are secretion and absorption. This epithelial type is found in the small collecting ducts of the kidneys, pancreas, and salivary glands.