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[breyn-stem] /ˈbreɪnˌstɛm/
the portion of the brain that is continuous with the spinal cord and comprises the medulla oblongata, pons, midbrain, and parts of the hypothalamus, functioning in the control of reflexes and such essential internal mechanisms as respiration and heartbeat.
Origin of brainstem
1875-80; brain + stem1 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for brain stem
  • The brains of reptiles correspond more or less to the structures known in mammals as the brain stem and the cerebellum.
  • Basic life functions such as breathing, blood flow and heartbeat are controlled by the brain stem, located at the brain's base.
  • His brain swelled, squeezed the brain stem, and stopped his heart.
  • The brain stem for the chicken would be kept intact so that the homeostatic functions continue to operate, allowing it to grow.
  • First, he emphasizes other areas of the brain in the production of consciousness, especially the brain stem.
  • Nevertheless, the conventional wisdom on brain stem cells is changing these days.
  • But in one out of five cases, the disease seems to target only the spinal cord and brain stem.
  • The brain stem emits nerve impulses that control erectile function.
  • The nucleus for the vagus nerve lies in the brain stem.
  • During this phase, there are rhythmic bursts of activity in the brain stem.
British Dictionary definitions for brain stem


the stalklike part of the brain consisting of the medulla oblongata, the midbrain, and the pons Varolii
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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brain stem in Medicine

brain stem or brainstem
The portion of the brain, consisting of the medulla oblongata, pons Varolii, and mesencephalon, that connects the spinal cord to the forebrain and cerebrum.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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brain stem in Science
The part of the vertebrate brain located at the base of the brain and made up of the medulla oblongata, pons, and midbrain. The brainstem controls and regulates vital body functions, including respiration, heart rate, and blood pressure. See also reticular formation.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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