A flow control valve, comprising a flow controlling valve configured to deflect from a generally planar posture to an increasingly nonplanar posture responsive to a relative increase in pressure difference and flow across the valve element; and a support element including a support structure supporting the valve element in its undeflected state; at least a first contact surface recessed from the support structure and configured to engage the valve element only when the valve element is deflected; and a flow passage wherein an effective flow-through volume through the at least one opening and the flow passage decreases as deflection of the valve element increases.