Medulla oblongata:

frequently referred to simply as the medulla, the medulla oblongata is the lowest portion of the brainstem and the point where the spinal cord connects to the brainstem. It contains a number of important tracts and nuclei, including nuclei that are necessary for maintaining vital functions like heart rate and respiration.

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Know your brain: Medulla oblongata

2-Minute Neuroscience: Medulla oblongata