The central nervous system is made up of the brain and spinal cord, and it works with the peripheral nervous system to receive, translate and respond to stimuli. Between the two systems, almost every function performed by the human body is regulated or affected.
Brain
The brain works in much the same way as a computer. The brain is made up of the cerebrum, cerebellum, pons and medulla. The brain is also divided into two hemispheres, the right and the left. The right side of the brain is responsible for logical thought, while the left side centers around creativity, imagination and intuition.
The brain receives messages from throughout the body, translates them into usable information, then sends back responses to the nerves and the muscles in the body. It is responsible for regulating the homeostatic, or involuntary processes in the body, such as blood pressure, body temperature, breathing and heart rate.
Spinal Cord
The spinal cord is located inside the connecting vertebrae of the back's spinal column. It connects with the brain via the brain stem. The spinal cord connects to the rest of the body through a series of 31 pairs of spinal nerves. These nerves radiate outward and comprise the peripheral nervous system. Each of these nerves connect to the spinal cord by two roots, a dorsal root and a ventral root.
The dorsal root sends information to the spinal cord, which then forwards it to the brain. The ventral roots receive information from the brain through the spinal cord and transmit it throughout the body.
Illnesses That Affect the Brain
Several illnesses affect the brain and the way it interacts with the rest of the body. Diseases such as Alzheimer's and dementia affect the way the brain processes information. Other diseases such as epilepsy affect the way the brain communicates with the body. Epilepsy is caused by an over-stimulation of the brain cells, while a stroke is caused by lack of oxygen to the brain. Lack of oxygen can be caused by blocked or clogged arteries that supply the brain with oxygen and other nutrients.
Trauma to the Spinal Cord
Severe injury or trauma to the spinal cord can cause permanent and irreversible paralysis. Where the injury occurs along the spinal cord can determine how much of the body is affected. Paraplegics are usually paralyzed from the waist down. Quadriplegics are normally paralyzed from the neck down. Many quadriplegics must remain on a ventilator due to the lack of stimuli to the lungs.
Meninges
The brain and spinal cord are covered by the meninges, which are three layers of connective tissue. The pia layer is closest to the brain and spinal cord and contains the small blood vessels that nourish them. The arachnoid, or middle layer, resembles a spider's web. It loosely encompasses the pia layer. The outermost layer is the dura mater. This layer forms barriers in the skull that protects the brain from sudden and abrupt movements.
Meningitis is an infection that affects these three layers of tissue. When the meninges are attacked by a virus or bacteria, they swell and put pressure on the brain and spinal cord. If meningitis is left untreated and the pressure becomes too severe, death may occur.
