The systemic and pulmonary circuits are crucial components of the circulatory system, working together to transport blood between the heart, lungs, and the rest of the body. The process begins with pulmonary circulation, where deoxygenated blood is pumped from the right ventricle to the lungs via the pulmonary trunk and arteries. Upon reaching the lungs, the blood becomes oxygenated and returns to the heart, specifically to the left atrium, via the pulmonary veins.
The oxygenated blood is sent from the left atrium to the left ventricle, marking the start of systemic circulation. This circuit transports blood from the heart to all parts of the body. As the blood leaves the left ventricle, it enters the ascending aorta, passes through the aortic arch, and is carried by the descending aorta to various tissues throughout the body.
During this journey, the blood exchanges gases and nutrients with the surrounding tissues, becoming deoxygenated in the process. This deoxygenated blood makes its way back to the heart, entering the right atrium via systemic veins. These include the superior vena cava, which carries blood from above the diaphragm; the inferior vena cava, which carries blood from below the diaphragm; and the coronary sinus, which carries blood from the myocardium. From the right atrium, the blood is pumped to the right ventricle, repeating the cycle of pulmonary circulation.
The pulmonary and systemic circuits work sequentially to move blood between the heart, lungs, and peripheral tissues.
Pulmonary circulation transports blood between the heart and lungs.
The right ventricle pumps deoxygenated blood to the pulmonary trunk, which divides into the left and right pulmonary arteries, delivering the blood to the lungs for oxygenation.
Next, the pulmonary veins carry the oxygenated blood to the left atrium, which then sends the blood to the left ventricle.
Systemic circulation begins here and transports blood between the heart and the entire body.
Blood from the left ventricle enters the ascending aorta, reaching the aortic arch and descending aorta, which carry it throughout the body.
After exchanging gases and nutrients with the surrounding tissues, the blood gets deoxygenated and enters the right atrium via the systemic veins.
The superior vena cava carries blood from regions above the diaphragm, the inferior vena cava from regions below, and the coronary sinus from the myocardium.
The right atrium pumps blood to the right ventricle, restarting the cycle of pulmonary circulation.
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