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

This triggered a rapid, automatic reaction involving the brainstem and muscles.

From Science Daily • Mar. 25, 2026

Dr. Crawford noted, "We found that upper parts of the brainstem were more active when relieving facial pain, while lower regions were engaged for arm or leg pain."

From Science Daily • Nov. 4, 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

Using mice, the researchers pinpointed a group of brain cells in the frontal cortex that connects to the brainstem, where vital actions like breathing are controlled.

From Science Daily • Nov. 19, 2024

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