Blood flow through most organs in the systemic circuit is regulated primarily by increasing or decreasing the ________ activity to arteriolar smooth muscles in the organ. another form of regulation, called ________, depends upon the metabolic activity of the organ. increased activity leads to increased interstitial fluid metabolites, which cause ___ of the arterioles. the former is a type of ________ regulation of blood flow; the latter is an example of ________ regulation.