Ductal is an adjective used to describe structures that pertain to ducts or are related to ducts. Synonyms for ductal include canalicular, tubular, piping or channel-like. These words are used to describe the narrow and elongated structures that transport fluids such as blood, urine, bile, and sweat. Canalicular refers to the small channels that connect cells or structures to larger ducts, such as the bile canaliculi. Tubular pertains to structures that are shaped like tubes or cylinders, such as the renal tubules in the kidneys. Piping is also a synonym for ductal and refers to structures that are tube-like or have a tubular shape, such as the alimentary canal. Channel-like is a term used to describe structures that are similar to channels, such as the lactiferous ducts in the mammary glands.