Final answer:
Systemic circulation is the process by which oxygen-rich blood is distributed from the heart to the rest of the body, and oxygen-poor blood returns to the heart. The correct description of systemic circulation is blood circulation to the entire body. It involves the heart, arteries, capillaries, veins, and does not solely pertain to the lungs or brain.
Step-by-step explanation:
Systemic Circulation
Systemic circulation is the part of the cardiovascular system responsible for transporting oxygen-rich blood from the heart to all parts of the body and returning oxygen-poor blood back to the heart. This vital process begins as the oxygenated blood leaves the left ventricle of the heart and enters the aorta. As the blood travels through the arterial system, it reaches the organs and tissues, delivering the essential oxygen and nutrients. Following this exchange at the cellular level, the now deoxygenated blood is collected via the venous system, ultimately flowing into the superior and inferior vena cava, and returns to the heart, completing the systemic circuit.
Incorrectly associating the systemic circulation with only the lungs, brain, or merely the blood circulation to and from the heart does not adequately describe the comprehensive reach of this circuit, which provides for the metabolic needs of all body tissues. Therefore, as per the available options, the correct description of systemic circulation is Blood circulation to the entire body.
In summary, upon completing the systemic circuit, the deoxygenated blood enters the pulmonary circulation where it is reoxygenated in the lungs before beginning another systemic journey.