Speed and duration of nervous and hormonal control

The body can coordinate activity using signals carried along nerves or chemical messengers carried in the blood. These two methods differ in how quickly they act and how long their effects generally last.

Nervous control acts rapidly because signals travel quickly along nerves to the parts of the body that respond. Its effects are generally short-lived: the response usually does not continue for long after the signalling stops.

Hormonal control uses chemical messengers called hormones. They travel in the blood to target organs, so their effects generally begin more slowly than those of nervous control. Hormonal effects also tend to last longer.

Speed and duration describe different features of a response: speed is how quickly an effect begins, whereas duration is how long the effect lasts. Nervous control is generally rapid and short-lived; hormonal control is generally slower and longer-lasting.