A lobule is a small, rounded section of an organ or tissue in the body. It is often used to describe the structural units found in various organs, such as the liver, lungs, and breasts. Each lobule can perform specific functions and is typically surrounded by connective tissue. In the liver, for example, lobules are made up of liver cells called hepatocytes, which help in processing nutrients and detoxifying substances. In the lungs, lobules contain clusters of alveoli, where gas exchange occurs. Understanding lobules is important for studying organ function and health.