The systemic circuit is a part of the cardiovascular system that carries oxygen-rich blood from the heart to the rest of the body. It begins when the left ventricle of the heart pumps blood into the aorta, the largest artery. From there, the blood travels through smaller arteries and arterioles, delivering oxygen and nutrients to tissues and organs. After the exchange of gases and nutrients, the now oxygen-poor blood returns to the heart through a network of veins. It enters the right atrium, completing the circuit. This process is essential for maintaining the body's overall health and function.