aivoperäistä

The aivoperäistä, known in English as the brainstem, is the central core of the vertebrate nervous system that connects the cerebrum with the spinal cord. It is composed of three primary regions: the midbrain, pons, and medulla oblongata, each of which contains both white and gray matter and houses numerous cranial nerve nuclei and ascending and descending axonal tracts.

Anatomically the brainstem is responsible for regurgitating sensory input and motor output between the brain and the rest of the body, as well as regulating essential functions such as breathing, heart rate, and blood pressure. The midbrain contains the superior and inferior colliculi, structures involved in visual and auditory processing, whereas the pons houses the pontine nuclei and serves as a relay for motor signals between the cerebrum and cerebellum. The medulla oblongata innervates autonomic centers that control pain reflexes, coughing, vomiting, and various cranial nerves that govern facial movement and swallowing.

In clinical settings, lesions of the brainstem can produce a multitude of deficits, from cranial nerve palsies to life‑threatening disruptions of the respiratory rhythm. Stroke, tumor infiltration, and traumatic injury are common etiologies. Diagnostic imaging with MRI or CT scans is essential for visualizing structural damage, while electrophysiological tests such as evoked potentials can assess functional integrity. Early recognition and management of brainstem pathology remain critical for preserving vital functions and improving patient outcomes.