The beaker in the model is used to simulate which cardiovascular parameter?

The beaker in the model is used to simulate which cardiovascular parameter?

• A. Afterload
• B. Preload
• C. Heart rate
• D. Stroke volume

Answer: (A)

Afterload is the pressure the ventricle must overcome to eject blood. In the model, the beaker at the outlet creates back-pressure against the pump. The height of the fluid in the beaker generates hydrostatic pressure that the ventricle has to exceed to push flow forward. As the beaker's height or its fluid content increases, the opposing pressure rises, just like higher arterial pressure or systemic resistance makes afterload higher in the body. That’s why the beaker is used to simulate afterload. Preload depends on how much fluid fills the ventricle before contraction, heart rate is how often the heart beats, and stroke volume is the amount ejected per beat—none of which are set by this outlet beaker.

Afterload is the pressure the ventricle must overcome to eject blood. In the model, the beaker at the outlet creates back-pressure against the pump. The height of the fluid in the beaker generates hydrostatic pressure that the ventricle has to exceed to push flow forward. As the beaker's height or its fluid content increases, the opposing pressure rises, just like higher arterial pressure or systemic resistance makes afterload higher in the body. That’s why the beaker is used to simulate afterload. Preload depends on how much fluid fills the ventricle before contraction, heart rate is how often the heart beats, and stroke volume is the amount ejected per beat—none of which are set by this outlet beaker.