Anatomical structure refers to the arrangement and organization of different parts within an organism. This includes various systems, such as the skeletal system, muscular system, and nervous system, each composed of specific organs and tissues that work together to perform essential functions. Understanding these structures helps in studying how organisms function and interact with their environment. In humans, for example, the heart is an anatomical structure that pumps blood throughout the body, while the lungs facilitate gas exchange. Each structure has a unique shape and function, contributing to the overall health and efficiency of the organism.