Why is the pressure in the pulmonary circulation lower than in the systemic circulation?

• A. The systemic circulation contains less blood than the pulmonary circulation.
• B. The left ventricle generates less force than the right ventricle.
• C. The pulmonary circuit has a shorter distance to pump blood, requiring less force.
• D. The pulmonary arteries have thicker walls than systemic arteries.

Answer: (C)

Verified step by step guidance

1. Understand the difference between pulmonary and systemic circulation: Pulmonary circulation moves blood between the heart and lungs, while systemic circulation moves blood between the heart and the rest of the body.
2. Recognize the anatomical differences: The pulmonary circuit has a shorter distance to pump blood (from the heart to the lungs and back), whereas the systemic circuit must pump blood throughout the entire body.
3. Analyze the force generated by the ventricles: The left ventricle pumps blood into the systemic circulation and requires more force due to the longer distance and higher resistance. The right ventricle pumps blood into the pulmonary circulation and requires less force due to the shorter distance and lower resistance.
4. Consider the structure of the blood vessels: Pulmonary arteries have thinner walls compared to systemic arteries, which reflects the lower pressure needed in the pulmonary circuit.
5. Conclude that the pressure in the pulmonary circulation is lower because the pulmonary circuit has a shorter distance to pump blood, requiring less force from the right ventricle.