Sensing effectors make sense

'Housekeepers' of living organisms maintain salt and water balance, monitor blood sugar and schedule their work to the season and the time of day. In order to perform their chores, they rely on information about the status quo. The traditional concept of a sensor that communicates with a central comparator authorizing an effector, which was inspired by engineers, has become blurred in the search for morphological correlates of such regulatory cascades. In many cases, neurones, which are both sensory and neurosecretory, and endocrine cells equipped with smart detectors, reliably regulate autonomous functions by using local rather than central computing. Like the well-trained staff of a smoothly run household, such 'sensing effectors' translate information into action.