Deoxygenated blood flows from your body to your heart through the Vena Cava. Superior Vena Cava drains the blood from your arms and head, the Inferior Vena Cava drains the Thorax, Abdomen, Pelvis and Legs.
From the Vena Cava, blood enters the heart at the right atrium, which passes through the tricuspid valve into the right atrium. The blood then passes through the pulmonic valve into the pulmonary arteries to get oxygenated in the lungs.
Oxygenated blood then flows back to the left atrium and passes through the mitral valve to the left ventricle. The left ventricle pumps blood through the aortic valve into the ascending aorta. In between beats, when the aortic valve closes, the coronary sinuses open and allow some blood to pass into the coronary arteries around the heart. However, most of the blood goes up the ascending aorta to the arch of the aorta, down the thoracic aorta and to the abdominal aorta. There are several arterial branches that separate the blood and deliver the oxygenated blood to the various body parts.