The Nervous System

The nervous system is an interconnected network of cells, tissues, and organs that directs and coordinates the body’s activities. It gathers information from inside the body and the surrounding environment, processes that information, and sends signals that guide responses. It has two main divisions: the central nervous system (CNS), made up of the brain and spinal cord, and the peripheral nervous system (PNS), which consists of the nerves connecting the CNS to the rest of the body.

Neurons, also called nerve cells, are the primary signaling cells of the nervous system. They communicate through electrical impulses and chemical messengers. Each neuron has three main components: a cell body, dendrites, and an axon. The cell body houses the nucleus and other cellular structures. Dendrites receive incoming messages from other neurons, while the axon carries signals to other neurons or cells, including muscle cells.

The nervous system supports sensory perception, movement, and mental activities. Sensory neurons carry information from sensory receptors to the CNS for interpretation and integration. Motor neurons send instructions from the CNS to muscles and other responding organs, enabling movement and other bodily processes. Within the CNS, interneurons connect and communicate with other neurons, supporting complex processing involved in memory, learning, and decision-making. Specialized cells known as glial cells help maintain, support, and protect neurons. Examples include astrocytes, oligodendrocytes, and microglia.