The brain stem
The brain stem is located at the base of the skull, below the cerebrum and is hidden by it. It is three inches long and the width of a thumb. The brain stem is a crucial part of the brain and if injured often results in death. It is the automatic part of the brain that controls the essential life processes such as breathing, heartbeat, digestion, and waste removal. Since it is essential to life, it functions automatically without conscious thought through the autonomic nervous system. It has three main parts: the midbrain, the pons, and the medulla. The parts of the brain stem help control reflex actions like sneezing, coughing, swallowing, and vomiting. The medulla is the lowest part of the brain and merges with the spinal cord. Ten pairs of cranial nerves, three through twelve, join the brain stem. Many nerve fibers cross from one side of the brain to the other through the medulla (Farley et al., 2014) (Roca & Serrano, 1996) (Olesky, 2001) (Parker, 1997) (Walker & Wood, 2003).