What are the 3 portions of the brain stem and what do each do?

Answer: The brain stem is a terminology used to refer collectively to the midbrain, pons, and medulla oblongata.

Explanation:

The midbrain is composed primarily of the optic lobes, which receive and process visual information it is responsible for reflexes involving eyes and ears. Pons is responsible for the reticular activating system and visceral control. The Medulla Oblongata is responsible for the sensory nuclei, reticular activating system, and visceral control.