Most academic institutions reflect the divide of the disciplines in their administrative structure, being divided internally into "departments" or "programs" in various fields of study. Each department is typically administered and funded separately by the academic institution, though there may be some overlap and faculty members, research and administrative staff may in some cases be shared among departments. In addition, academic institutions generally have an overall administrative structure (usually including a president and several deans) which is controlled by no single department, discipline, or field of thought. Also, the tenure system, a major component of academic employment and research in the US, serves to ensure that academia is relatively protected from political and financial pressures on thought.