Intercellular communication (ICC) refers to the various ways and structures that biological cells use to communicate with each other directly or through their environment. Often the environment has been thought of as the extracellular spaces within an animal. More broadly cells may also communicate with other animals, either of their own group or species, or other species in the wider ecosystem. Different types of cells use different proteins and mechanisms to communicate with one another using extracellular signalling molecules or electric fluctuations which could be likened to an intercellular ethernet.[2] Components of each type of intercellular communication may be involved in more than one type of communication[2] making attempts at clearly separating the types of communication listed somewhat futile. Broadly speaking, intercellular communication may be categorized as being within a single animal, or between an animal and other animals in the ecosystem in which it lives. In this article intercellular communication has been further collated into various areas of research rather than by functional or structural characteristics.