The cystic duct is a small tube that connects the gallbladder to the common bile duct. It plays a crucial role in the transport of bile, a digestive fluid produced by the liver. When food enters the small intestine, the gallbladder releases bile through the cystic duct to aid in digestion. The cystic duct can become blocked due to gallstones or inflammation, leading to conditions such as cholecystitis. This blockage can cause pain and other digestive issues, making it important for the cystic duct to function properly for overall digestive health.