The brain stem controls the flow of messages between the brain and the rest of the body, and it also controls basic body functions such as breathing, swallowing, heart rate etc... The brainstem is divided into three sections in humans: the midbrain (mesencephalon) which governs rudimentary vision and hearing, pons varolii (metencephalon) which links the cerebellum to the cerebrum and the medulla oblongata (myelencephalon) which controls breathing, swallowing, blood pressure, and heart rate.