1 Introduction; 2 Stomach; 3 Small intestine; 4 Duodenum; 5 Colon; 6 Caecum; 7 Ileocaecal Junction; 8 ICC found in the submucosal layer; 9 Ultrastructural demonstration of ICC; 10 Signal-pathways between the nerves and muscles not by means of ICC; 11 Issues for future studies