Stanley Jacobson, Elliott M. Marcus
The Central Nervous System consists of the spinal cord and brain. The spinal cord is found in the vertebral column and the brain is housed in the cranium/skull. The spinal cord has 32 segments and the brain consists of the brain stem, diencephalon, cerebellum, and cerebrum. At the foramen magnum, the highest cervical segment of the spinal cord is continuous with the lowest level of the medulla of the brain stem. The 12 cranial nerves attached to the brain form the upper part of the part of the peripheral nervous system and record general sensations of pain, temperature, touch, and pressur; in addition, we now find the presence of the special senses of smell, vision, hearing, balance, and taste. The blood supply to the brain originates from the first major arterial branches from the heart, ensuring that over 20% of the entire supply of oxygenated blood flows directly into the brain.