brainstem

/brayn"stem'/, n.
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.
Also, brain stem.
[1875-80; BRAIN + STEM1]

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      area at the base of the brain that lies between the deep structures of the cerebral hemispheres and the cervical spinal cord. It is divided into three sections: midbrain (mesencephalon), pons (metencephalon), and medulla oblongata (myelencephalon). The brainstem houses many of the control centres for vital body functions, such as swallowing, breathing, and vasomotor control. All of the cranial nerve nuclei, except those associated with olfaction and vision, are located in the brainstem, providing motor and sensory function to structures of the cranium, including the facial muscles, tongue, pharynx, and larynx, as well as supplying the senses of taste, equilibrium, and hearing. The brainstem also has nuclei important for sympathetic and parasympathetic autonomic functions. All efferent and afferent pathways between the cerebrum and cerebellum course through the brainstem, and many of them decussate, or cross, within this structure. Because of the important neural structures concentrated in this small portion of the nervous system, even very small lesions of the brainstem may have profound effects. Disorders involving the brainstem include trauma, tumours (tumour), strokes (stroke), infections, and demyelination ( multiple sclerosis). Complete loss of brainstem function is regarded by some experts as equivalent to brain death.

Robert Joynt
 

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Universalium. 2010.

Look at other dictionaries:

  • brainstem — [brān′stem΄] n. a stalklike structure at the base of the brain that connects the spinal cord with the cerebrum and includes the medulla oblongata, pons, and midbrain: also written brain stem …   English World dictionary

  • brainstem — UK [ˈbreɪnˌstem] / US noun [countable] Word forms brainstem : singular brainstem plural brainstems medical the part of the brain above the spinal cord between the left and right halves of the brain …   English dictionary

  • brainstem — n. the enlarged extension upwards within the skull of the spinal cord, consisting of the medulla oblongata, the pons, and the midbrain. The pons and medulla are together known as the bulb, or bulbar area. Attached to the midbrain are the two… …   Medical dictionary

  • brainstem — n. (Anatomy) part of the lower brain that resembles a stem and connects the brain to the spinal cord …   English contemporary dictionary

  • brainstem — noun Anatomy the central trunk of the mammalian brain, consisting of the medulla oblongata, pons, and midbrain …   English new terms dictionary

  • brainstem — n. the enlarged extension upwards within the skull of the spinal cord, consisting of the medulla oblongata, the pons, and the midbrain. The pons and medulla are together known as the bulb, or bulbar area. Attached to the midbrain are the two… …   The new mediacal dictionary

  • brainstem — brain′stem or brain′ stem n. anat. the portion of the brain that is continuous with the spinal cord and in mammals comprises the medulla oblongata and parts of the midbrain • Etymology: 1875–80 …   From formal English to slang

  • brainstem — noun the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus • Syn: ↑brain stem, ↑brain stem • Hypernyms: ↑neural structure • Part Holonyms: ↑brain,… …   Useful english dictionary

  • Brainstem auditory hallucinosis —    A term used to denote a hallucinatory state characterized by * auditory hallucinations which are attributed to aberrant neurophysiological activity in the brainstem. The concept of brain stem auditory hallucinosis is analogous to that of *… …   Dictionary of Hallucinations

  • Brainstem glioma — A brainstem glioma is a glioma tumor in the brainstem.External links* [http://www.emedicine.com/NEURO/topic40.htm Brainstem glioma information on Emedicine] …   Wikipedia

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