medulla

/məˈdʌlə/

/məˈdʌlə/

Other forms: medullas; medullae

Definitions of medulla

1. noun

   the inner part of an organ or structure in plant or animal
   antonyms:

   cortex

   the tissue forming the outer layer of an organ or structure in plants or animals

   types:

   adrenal medulla

   the medulla of the adrenal gland; secretes epinephrine

   type of:

   animal tissue

   the tissue in the bodies of animals

   plant tissue

   the tissue of a plant
2. noun

   a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers
   synonyms: myelin, myeline

   type of:

   fat

   a soft greasy substance occurring in organic tissue and consisting of a mixture of lipids (mostly triglycerides)
3. noun

   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”

   synonyms: bulb, medulla oblongata

   type of:

   neural structure

   a structure that is part of the nervous system