Interruptions are an often lamented and frequently studied aspect of clinical practice. However, some interruptions, such as updates on patient care decisions and notifications of detrimental patient lab values, are in fact necessary to the work process. In this paper, we explore the interruptions as an emergent feature of communication in teams. Looking beyond the frequency of interruptions, we consider the source and intent of interruptions with the goal of discovering the functions served by such communications. Furthermore, in this study of an emergency department, we classify interruptions into those activities that support required work and those interruptions that create unnecessary breaks in workflow. The intent of our larger body of work is to develop health information technology systems that support team efforts including the functions currently served by interruptions.