Which circulation carries oxygenated blood to the body from the heart and returns deoxygenated blood from the body to the heart?

• A. Systematic circulation
• B. Pulmonary circulation
• C. Coronary circulation
• D. Portal circulation

Answer: (A)

Systemic circulation is the pathway that moves oxygen-rich blood from the left side of the heart out to all body tissues and returns oxygen-poor blood back to the right side of the heart. Oxygenated blood leaves the left ventricle into the aorta, travels through arteries to body tissues where oxygen is delivered, and the blood becomes deoxygenated as CO2 is picked up. It then returns through veins to the right atrium, completing the loop. This is different from pulmonary circulation, which carries blood to the lungs to be oxygenated, coronary circulation, which nourishes the heart muscle itself, and portal circulation, which delivers blood from abdominal organs to the liver.