- myelin, myeline, medulla - a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers
--1 is a kind of fat
--1 is a substance of medullary sheath, myelin sheath - medulla oblongata, medulla, bulb - lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata); "the medulla oblongata is the most vital part of the brain because it contains centers controlling breathing and heart functioning"
--2 is a kind of neural structure
--2 is a part of brainstem, brain-stem, brain stem
--2 has parts: respiratory center - medulla - the inner part of an organ or structure in plant or animal
--3 is a kind of animal tissue; plant tissue
Antonyms: cortex
--3 has particulars: adrenal medulla