Figure 4. Electrical model of the peripheral vasculature. A current generator forces current through two resistances representing, respectively, the arterial and venous components of the total peripheral resistance. Capacitances represent the hydraulic capacitance of the vasculature, divided into three components: arterial, peripheral venous (venular), and central venous. Total charge in the system represents the total volume contained within the vasculature. Charge contained in each capacitor equals the product of voltage and capacitance. Electrical ground corresponds to the zero reference for pressure. Volume within each of the subdivisions of the total volume is represented by the product of the individual capacitance and its voltage (pressure).