Brainstem

About the Brainstem

The brainstem connects the cerebrum and cerebellum to the spinal cord and is made up of three parts: the midbrain, the pons, and the medulla oblongata. Almost all nerve fibers traveling between the brain and the body pass through it, including the major motor and sensory pathways. It also contains the nuclei of ten of the twelve pairs of cranial nerves, which control eye movement, facial sensation and expression, hearing, balance, swallowing, and the voice. Centers in the medulla and pons regulate breathing, heart rate, and blood pressure, and the reticular formation running through the brainstem is essential for wakefulness and consciousness. Because so many vital functions are concentrated in a small space, damage from stroke, bleeding, or compression can have severe effects, and the permanent loss of all brainstem function is a central element in the clinical determination of death by neurological criteria.