Final answer:
The medulla oblongata serves as the bidirectional passageway connecting the cerebrum and the spinal cord, and it's part of the brainstem which coordinates many vital functions.
Step-by-step explanation:
The medulla oblongata is the bidirectional passageway for all tracts connecting the cerebrum and the spinal cord. The brainstem consists of the medulla oblongata, the pons, and the midbrain, where motor and sensory neurons extend through to allow for the relay of signals between the brain and spinal cord. The brainstem is also responsible for coordinating multiple functions such as breathing, blood pressure, and heart rate, making it an integral part of the central nervous system.