or larger. The hindbrain is made up of the cerebellum and parts of the brainstem. The cerebellum is involved in controlling bodily position, muscular coordination, and emotions. It contains neurons called Purkinje cells, which is connected to more than 100,000 nerve fibers and makes more connections than any other type of nerve cells. The medulla oblongata is located at the lowest part of the brainstem. It controls reflexes like heartbeat, breathing, and swallowing. Any messages being carried to the muscles pass through the medulla. Located at the rear of the medulla is a group of neurons that acts as the brain’s warning system. The medulla also organizes sleeping and waking by stopping messages being sent to the brain when we are sleeping, and sends it through the brain when we awake. Three membranes surround the brain: the dura, arachnoid, and pia. Between the arachnoid and pia is the cerebrospinal fluid. Cerebrospinal fluid is a clear fluid that protects the brain while the head is moving. The brain produces 500 milliliters of these fluids a day. The spinal cord is located below the brain and is connected to the brainstem. It is a cylinder of 31 spinal nerves about 18 inches long. The spinal cord is made up of gray and white matter, with the white matter surrounding the gray. The spinal cord is encased in cerebrospinal fluid and wrapped in three layers of membrane. All messages sent to and from the brain travels through the spinal cord because the brain can’t read what its neurons cannot contact. The spinal cord processes sensory information, like temperature, to the brain. The spinal cord is also necessary for movement of the body and reflexes that doesn’t involve the brain. Any damage to the spinal cord will cause paralysis and anesthesia because its connection to the brain is severed. Damage to the cord is permanent because the neurons can’t be regenerated. Peripheral Nervous SystemThe peripheral nervous sy...
