Abstract: An improved blood reservoir formed by opposed, flexible sheets has a screen sandwiched between the sheets defining an input chamber, an output chamber, and vent chamber. A vent is in fluid communication with the vent chamber. An outlet is in fluid communication with the output chamber. One or more inlets direct blood into the input chamber through apertures that direct blood upward and along the screen, allowing gas bubbles entrained in the blood to escape through the vent. Support springs around the inlets allow them to be flexed without kinking. The reservoir can be coupled to an improved mounting board for use.