Marrow or pith. medulla oblongata, posterior part of brain joining it to spinal cord. medulla spinalis, spinal cord.
Central part of an organ. In the mammalian kidney, the medulla lies beneath the outer cortex and is responsible for the reabsorption of water from the filtrate. In plants, it is a region of packing tissue in the center of the stem. In the vertebrate brain, the medulla is the posterior region responsible for the coordination of basic activities, such as breathing and temperature control.
The inner part of an organ or structure in plant or animal.