Final answer:
The right and left ventricles generate different pressures because they pump blood through circuits with differing lengths and resistances. The right ventricle, responsible for the pulmonary circulation, requires less pressure, while the left ventricle must generate higher pressure for systemic circulation, both ensuring equal stroke volume.
Step-by-step explanation:
It is necessary for the right and left ventricles to force blood out of the heart at pressures of approximately 4kPa and 16kPa, respectively, due to the different circulatory paths and resistances they encounter. The right ventricle pumps blood through the pulmonary circuit, which is shorter and has less resistance compared to the systemic circuit. Therefore, it requires less pressure to move blood through the lungs. On the other hand, the left ventricle pumps blood through the systemic circuit, which is much longer and encounters greater resistance from the entire body. Due to this high resistance, the left ventricle must generate a significantly greater pressure to ensure effective blood flow throughout the body. Additionally, both ventricles must eject the same stroke volume, the quantity of blood that includes about 70–80 mL, to maintain a balanced and consistent circulatory system.