Fig. 1. Schematic demonstrating the excised mesenteric artery mounted on micropipettes. An air microbubble has been injected using a small diameter micropipette to puncture the vessel wall. A = bubble cross-sectional area in the plane perpendicular to the axis of the vessel; D = vessel (and microbubble) internal diameter; L = microbubble length; P¹= inflow pressure; P²= outflow pressure. Mounted vessel length was 3.5–4 mm.