1.Definition: a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers

Related Noun(s):myelin, myeline

Category: General

2.Definition: 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"

Related Noun(s):bulb

Category: General

3.Definition: the inner part of an organ or structure in plant or animal

Category: General