Which part of an organ is referred to as the medulla?

The medulla refers to the central portion of an organ. In anatomy, many organs have distinct layers or sections, and the medulla is typically the innermost part, surrounded by other structures. For instance, in the kidneys, the medulla is the inner region that plays an essential role in kidney function, including the concentration of urine. Similarly, in the adrenal glands, the medulla is involved in hormone production, particularly the stress hormones like adrenaline. Understanding this terminology is crucial for describing organ structures, functions, and processes in various biological contexts, especially in oncology, where organ anatomy can significantly influence treatment approaches and outcomes.