parenchyma

This term describes the essential, working parts of an organ, contrasting with the stroma, which provides the structural framework. In medical contexts, it refers to the cells that perform the specific physiological function of the organ, such as the nephrons in the kidney or the alveoli in the lungs. In botany, it refers to the versatile ground tissue of plants. These cells are typically thin-walled and capable of dividing or specializing for storage and photosynthesis, serving as the primary filler tissue between dermal and vascular layers.