The |brain| is the primary component of the nervous system, occupying the cranial cavity. Without its outermost protective membrane, the |dura mater|, the |brain| weighs an average of three pounds (about 1.4 kilograms), comprising about 97% of the entire central nervous system. The |brain| is connected to the upper end of the |spinal cord| (which connects through the |foramen magnum| of the |skull|) and is responsible for issuing ~nerve~ impulses, processing ~nerve~ impulse data, and engaging in the higher order thought processes. The |brain| is divided into three parts: the large |cerebrum|, the smaller |cerebellum|, and the brainstem leading to the |spinal cord|. The brainstem is also descriptively divided into the |medulla| oblongata, the midbrain, and the |pons|.
