The aim of this chapter is to focus on the nervous system. Nervous system consists of nerve cells and special supporting cells of the nervous system, the neuroglial cells. Nervous system is classified as based on location and based on function. Neurons are specialized cells for conducting the impulses. They do not undergo cell division except the olfactory neurons. Neuroglia is special connective tissue cells present only in the nervous system. They are nonexcitable. They multiply by mitotic cell division. Brain is one of the vital organs. It is lodged in the cranial cavity, well protected by the skull bones and the three layered cranial meninges. There are three major subdivisions such as prosencephalon or forebrain, mesencephalon or midbrain, and rhombencephalon or hindbrain. Brain develops from cranial part of neural tube, which is derived from neurectoderm. Retina and optic nerve as well as neurohypophysis are the extensions of neural tube.