Neural System

Every living cell in the body needs to know what is happening around it and respond in a coordinated way, and that job belongs to the neural system. It is built from highly specialised cells called neurons, which are unlike ordinary cells because their entire job is to detect a stimulus, receive it, process it, and pass it on as an electrical signal. In simple invertebrates this job is done by a loosely connected mesh of neurons called a nerve net, but in higher animals the neural system is far more organised and centralised.

A well-developed neural system, such as ours, carries out three broad jobs. Its sensory function picks up information from both inside the body (like blood pressure or hunger) and outside it (like light, sound or touch). Its motor function carries commands outward from the brain to the skeletal muscles so that we can move voluntarily. Its autonomic function covers the fast, automatic responses we call reflexes — actions the body takes without waiting for conscious decision-making, such as pulling a hand away from something hot. These three functions together explain w …