What term describes the functional parts of an organ?

The term that describes the functional parts of an organ is "parenchymal." This term specifically refers to the tissues that perform the essential functions of an organ, distinguishing them from the supporting structures. For instance, in the liver, hepatocytes are the parenchymal cells that carry out metabolic tasks, while other cell types contribute to structural support.

In contrast, stroma refers to the supportive framework of an organ, which includes connective tissues, blood vessels, and other non-functional cells that assist in maintaining the organ's structure. Interstitial typically describes the spaces between cells in a tissue, which may house fluid and other molecules but does not directly refer to the functional component itself. The term matrix usually describes the material or tissue in which more specialized structures are embedded, again not pinpointing the functional aspect of the organ. Therefore, parenchymal clearly captures the essence of the functional elements within an organ's architecture.