Final answer:
The right ventricle must generate enough pressure to overcome the low resistance of the pulmonary circuit to send blood to the lungs, requiring less force than the left ventricle due to the shorter distance and less resistance.
Step-by-step explanation:
The right ventricle projects its volume against a type of resistance that is significantly lower than that which the left ventricle faces. When the right ventricle contracts during the ventricular ejection phase of systole, it ejects blood into the shorter pulmonary circuit, which has less resistance compared to the systemic circuit. Unlike the left ventricle that must generate a high amount of pressure to overcome the resistance of the long systemic circuit and push blood throughout the entire body, the right ventricle needs to create enough pressure to send blood to the lungs via the pulmonary arteries. The resistance in the pulmonary circuit is lower as it is confined to the lungs, leading to a lesser degree of force needed from the right ventricle.
In the cardiac cycle, both ventricles eject the same stroke volume even though their pressures differ. The right ventricle has thinner walls and less muscle mass compared to the left ventricle, as illustrated in Figure 19.8, which shows the differences in muscle thickness necessary to overcome the varied resistances of the pulmonary and systemic circuits.