At a cellular level, communication takes place through cell signalling.One cell releases a chemical which has an effect on another cell.The second cell is known as the target cell.In the nervous system, the cells are known as neurones. The chemicals transmitted are called neurotransmittersIn the hormonal system chemicals called hormones are produced by glands and secreted directly into the blood. The blood transports the hormones around the body to all cells. Cells with receptors on their cell surface membrane specific for the hormone are called target cells. These cells are stimulated by the hormone.The response is slower, less specific, longer lasting and more widespread than neuronal communication.An example is the lowering of blood sugar by the hormone insulin.