brainstem

American  

[breyn-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

Example Sentences

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

The brainstem functions as the main communication pathway between the brain and spinal cord, directing signals that control thought, sensation, and survival responses.

From Science Daily • Nov. 4, 2025

This area of the brainstem receives interoceptive input, or signals from the body about its internal state, like hunger, pain and fullness.

From Salon • Feb. 6, 2025

What especially piqued Ruyle’s interest in the nTS is that it’s the first area of the brainstem to receive input from the large nerves that relay information about cardiorespiratory function.

From Salon • Feb. 6, 2025

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