AP BIOLOGY

Detailed explanation-1: -The nervous system of vertebrates has two main divisions: the central nervous system, consisting of the brain and spinal cord, and the peripheral nervous system, which in humans includes 12 pairs of cranial nerves, 31 pairs of spinal nerves, and the autonomic, or involuntary, nervous system.

Detailed explanation-2: -The central nervous system (CNS) is made up of the brain and spinal cord. It is one of 2 parts of the nervous system. The other part is the peripheral nervous system, which consists of nerves that connect the brain and spinal cord to the rest of the body.

Detailed explanation-3: -Adult vertebrate brains can be subdivided into three major territories: forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon) (Figure 1). Overall, the forebrain is the part that has changed the most in evolution, while the midbrain and hindbrain are relatively more conserved.

Detailed explanation-4: -The brain and spinal cord are the organs of the central nervous system. Because they are so vitally important, the brain and spinal cord, located in the dorsal body cavity, are encased in bone for protection. The brain is in the cranial vault, and the spinal cord is in the vertebral canal of the vertebral column.