What Are the Brain and Spinal Cord?
The brain and the spinal cord comprise the central nervous system. The brain is the center for interpreting and integrating information from all over the body. The spinal cord acts as a conducting system to relay information from the brain to various areas of the body.
Where Are the Brain and Spinal Cord Located?
The brain is located within the bony cranium or the skull. The spinal cord is located within the spinal canal that runs through the vertebral column (neck and back bone), and extends from the base of the skull down the middle of the tail.
What Is the General Structure of the Brain and Spinal Cord?
The brain is a mass of soft, pinkish gray nerve tissue divided into three major compartments: the brain stem, cerebrum and cerebellum.
Brain stem. The brain stem is located at the base of the brain and is connected to the spinal cord and cerebellum. Almost all of the cranial nerves (nerves that control various functions on the head) arise from the brain stem.
Cerebrum. The cerebrum, which forms the bulk of the brain, may be divided into two major parts: the right and left cerebral hemispheres. The hemispheres are divided by a narrow slit or cleft called the cerebral longitudinal fissure. The two sides of the brain are connected at the bottom by the corpus callosum, which delivers messages from one side to the other.
Cerebellum. The cerebellum is located at the back of the brain and is attached to the brain stem and cerebrum. The cerebellum functions chiefly to coordinate movement and posture.
The spinal cord is an elongated structure, more or less cylindrical, that is made up of the major bundle of nerve tracts that carry nerve impulses to and from the brain to the rest of the body. The spinal cord is connected to all areas of the body by nerves that leave and enter the spinal column through the gaps between the bony vertebrae.
Both the brain and the spinal cord are enclosed within the meninges, which consists of three tough membranes called the dura mater, arachnoid and pia mater. Cerebrospinal fluid (CSF) is produced within the brain in hollow channels called ventricles. This fluid surrounds the brain and spinal cord to protect them from injury. Both brain and spinal tissue can be subdivided into gray matter and white matter.
What Are the Functions of the Brain and Spinal Cord?
The brain governs various behaviors through learning, motivation and perception. It produces nerve impulses to make muscles move, to send signals to organs, and to control numerous automatic bodily functions. The brain also receives and registers sensory impulses, such as sight, sound, taste, touch, smell, and pain.
The spinal cord acts to coordinate movement and muscular activity. It also governs both automatic and voluntary reflexes, such as blinking, scratching, twitching the ears, and wagging the tail.
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