The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.

A small, rounded eminence on each side of the FOURTH VENTRICLE, which receives nerve fibers from the SOLITARY NUCLEUS; SPINAL CORD; and adjacent areas of the MEDULLA. The area postrema lies outside the BLOOD-BRAIN BARRIER and its functions include acting as an emetic chemoreceptor.