The regulation of blood flow from one perspective seems simple and straight-forward. For example in metabolically active organs like the heart and brain, as metabolic activity increases flow increases. The converse also happens if metabolic activity decreases, flow decreases. This process is called metabolic dilation or metabolic hyperemia. It is important to note that the exact mechanisms responsible for the process of metabolic dilation are currently unknown. Yet, it is understood that this process is imperative for the brain to function properly, the heart to pump, skeletal muscles to move, and the gastrointestinal system to absorb foodstuffs. Thus understanding how blood flow is regulated is critical to our understanding of life! We have developed some unique resources that have enabled us to determine some underlying mechanisms of metabolic dilation. The next few figures reveal some of these mechanism.