The nervous system is responsible for all behavior, thoughts, and actions in the body. It works with the endocrine system to maintain homeostasis. The nervous system has three main functions - sensory input, integration of information, and motor output responses. It is divided into the central nervous system (brain and spinal cord) and peripheral nervous system, with the peripheral system further divided into afferent and efferent divisions. Neurons are the basic structural and functional units of the nervous system and come in various types like multipolar neurons. Glial cells provide support and protection for neurons in the central and peripheral nervous systems. Certain drugs can artificially stimulate the brain's pleasure centers and rewire how neurotransmitters function, leading to addiction

1. The Nervous System

14. Multipolar Neuron