brainstem

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brainstem

 [brān´stem]
the stemlike portion of the brain connecting the cerebral hemispheres with the spinal cord, and comprising the pons, medulla oblongata, and midbrain; considered by some to include the diencephalon. Also written brain stem.

brain·stem

, brain stem (brān'stem), [TA]
Originally, the entire unpaired subdivision of the brain, composed of (in anterior sequence) the rhombencephalon, mesencephalon, and diencephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the term's connotation has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable.
Synonym(s): truncus encephali [TA]

brainstem

(brān´stem″) the stemlike portion of the brain connecting the cerebral hemispheres with the spinal cord, and comprising the pons, medulla oblongata, and midbrain; considered by some to include the diencephalon.

brainstem

or

brain stem

(brān′stĕm′)
n.
The portion of the brain, consisting of the medulla oblongata, pons Varolii, and midbrain, that connects the spinal cord to the forebrain and cerebrum.

brainstem

Etymology: AS, bragen + stemm
the portion of the brain comprising the medulla oblongata, the pons, and the mesencephalon. It performs motor, sensory, and reflex functions and contains the corticospinal and reticulospinal tracts. The 12 pairs of cranial nerves from the brain arise mostly from the brainstem. Compare medulla oblongata, mesencephalon, pons.

brainstem

The central stalk-like axis of the lower CNS, which connects the brain with the spinal cord.
 
Components
• Medulla oblongata;
• Pons;
• Midbrain;
• Diencephalon.
 
Functions
• Transmission and “lower cortical” processing of sensory neural impulses from the periphery and motor impulses to muscles and other effectors;
• Anatomic site of egress of cranial nerves 3 to 12;
• Reticular functions, integrating cardiorespiratory control, arousal and alertness, consciousness.

brain·stem

, brain stem (brān'stem) [TA]
Originally, the entire unpaired subdivision of the brain, composed of the rhombencephalon, mesencephalon, and diencephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the connotation of the term has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable.

brainstem

(brān′stĕm″)
Enlarge picture
BRAINSTEM
The stemlike part of the brain that connects the cerebral hemispheres with the spinal cord. It includes the diencephalin, midbrain, and hindbrain. Some anatomists do not include the diencephalon in the brainstem. See: illustration

brainstem

The part of the brain consisting of the medulla oblongata and pons, which connects the main brain (cerebrum) to the spinal cord. The brainstem contains the ‘vital centres’ for respiration and heart-beat and the nuclei of most of the CRANIAL NERVES as well as massive motor and sensory nerve trunks passing to and from the cord.

Brainstem

Brain structure closest to the spinal cord, involved in controlling vital functions, movement, sensation, and nerves supplying the head and neck.

brainstem

distal brain area, initiating and coordinating basic life reflexes (e.g. breathing, heart beat)

brain·stem

, brain stem (brān'stem) [TA]
Originally, the entire unpaired subdivision of the brain, composed of the rhombencephalon, mesencephalon, and diencephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the connotation of the term has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable.

brainstem,

n the portion of the brain comprising the medulla oblongata, pons, and mesencephalon. It performs motor, sensory, and reflex functions.

brainstem

the stemlike portion of the brain connecting the cerebral hemispheres with the spinal cord, and comprising the pons, medulla oblongata and midbrain; considered by some to include the diencephalon. See also reticular activating system, ascending reticular formation, thalamus.

brainstem auditory evoked response
see brainstem auditory evoked response.
brainstem hemorrhage
results from cranial trauma and characteristically causes unconsciousness with varying types and degrees of motor paralysis and irregularities of respiration, depending on the site.
brainstem reticular formation
see reticular activating system.