The human brain is composed of three major parts:
Each part has a special role to play in performing different tasks, ensuring the proper functioning of the brain and controlling the many functions of the body. These three parts work in tandem with several other key parts of the brain network to implement the activities of the brain.
The brain stem is connected to the spinal cord. The brain stem controls the body’s blood pressure, heart rate, basic reflexes, arm and leg movements, and digestion.
Within the brain stem are the pons, medulla, thalamus, and midbrain. Each of these have a designated task when it comes to the processing and sending out of information to the brain.
See brain stem in American Heritage Dictionary 4
also brain·stem
noun