What defines an organ in the context of human anatomy?

In human anatomy, an organ is defined by the presence of multiple tissues working together to perform specific functions. Each organ typically consists of several types of tissue, including epithelium, connective tissue, muscle tissue, and nervous tissue, all of which collaborate to enable the organ to carry out its role effectively. For example, the heart includes muscle tissue for pumping, connective tissue for structure, and nervous tissue for regulating its function.

While a single tissue type is essential for basic structure and function, it is the combination and interaction of different tissues that characterizes an organ. A type of cell refers to the fundamental unit of life in the body, but it does not constitute an organ by itself. Similarly, organelles are specialized structures within cells that perform certain functions, but they do not function at the organ level. Therefore, the concept of an organ is intrinsically linked to the collaboration of multiple tissue types for a shared purpose, highlighting the complexity of biological systems in the human body.