A demonstration device comprises a base having a front side, a back side, a respiratory port, a circulation port, a heart port and at least one lung port. The heart port is fluidly connected to the circulation port, and the lung port is fluidly connected to the respiratory port. A compressible member is sealed to the front side of the base to define a chamber over the lung port and the heart port. A lung member is disposed over the lung port, and a heart member is disposed over the heart port. In this way, when the compressible member is compressed and released, the lung member deflates and inflates and the heart member deflates and inflates.