brainstem

American  

[brayn-stem] / ˈbreɪnˌstɛm /

Or brain stem

noun

1. 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.

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brainstem British  

/ ˈbreɪnˌstɛm /

noun

1. the stalklike part of the brain consisting of the medulla oblongata, the midbrain, and the pons Varolii

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brainstem Scientific  

/ brān′stĕm′ /

1. 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.

2. See also reticular formation

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Etymology

Origin of brainstem

First recorded in 1875–80; brain + stem ¹

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Example Sentences

See Examples For:

brainstem

The researchers also examined the locus coeruleus, a tiny area deep within the brainstem that is roughly the size of a grain of rice.

From Science Daily ● Aug. 29, 2026

Other scientists say the atlas could also help neurosurgeons navigate the brainstem more safely.

From BBC ● Jul. 13, 2026

Built from high-resolution microscope images rather than costlier molecular techniques, it creates a detailed three-dimensional map of the brainstem, identifying more than 200 clusters of brain cells and nerve pathways.

From BBC ● Jul. 13, 2026

Once growth hormone enters the system, it activates the locus coeruleus, a brainstem region that controls alertness, attention, and cognitive function.

From Science Daily ● Mar. 30, 2026

Capping the brainstem is the R-complex, the seat of aggression, ritual, territoriality and social hierarchy, which evolved hundreds of millions of years ago in our reptilian ancestors.

From "Cosmos" by Carl Sagan

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