How the Body Works: The Motor Cortex

he motor cortex is the area in the brain which issues orders for body movement, and therefore, controls the voluntary muscle system of the body. The nerve impulses pass from the cortex and travel into the brain stem, along bundles of nerve fibers which cross in the medulla oblongata. Impulses from the right side of the brain thus control the left side of the body, and vice versa. The nerve impulses then pass from the medulla oblongata to fibers in the spinal cord and leave at each section as the motor roots to form the spinal nerves, which transmit the impulses to the muscles. Involuntary muscle movements are controlled by the autonomic nerves, which leave the motor root and then pass to nearby nerve chains.