Central nervous system (CNS): Your brain and spinal cord make up your CNS. Your brain uses your nerves to send messages to the rest of your body. Each nerve has a protective outer layer called myelin. Myelin insulates the nerve and helps the messages get through. Peripheral nervous system: Your peripheral nervous system consists of many nerves.

The first nerve root exits between S1 and S2. One pair of coccygeal (Co1) nerves meets in the area of the tailbone. By way of the peripheral nervous system (PNS), nerve impulses travel to and from the brain through the spinal cord to a specific location in the body. The PNS is a complex system of nerves that branch off from the spinal nerve.

The central nervous system (CNS) consists of the brain and the spinal cord, while the peripheral nervous system (PNS) consists of sensory neurons, ganglia (clusters of neurons) and nerves. Here is a diagram that you can refer to, while you read about the human nervous system function and parts.

The nervous system can be divided into two major regions: the central and peripheral nervous systems. The central nervous system (CNS) is the brain and spinal cord, and the peripheral nervous system (PNS) is everything else ( Figure 12.2 ).

The sympathetic nervous system (SNS): Neurons within the SNS generally prepare the body to react to something in its environment. For example, the SNS may increase heart rate to prepare a person.

The endocrine system consists of cells, tissues, and organs that secrete hormones critical to homeostasis. The body coordinates its functions through two major types of communication: neural and endocrine. Neural communication includes both electrical and chemical signaling between neurons and target cells.