The heart is located in the thoracic cavity nestled between the lungs on the body's midline.
Pigs like other mammals have a four-chambered heart. The right side of the heart pumps blood to the lungs (pulmonary circulation), and the left side pumps blood out to the rest of the body (systemic circulation). Each side of the heart has two chambers, the upper chambers are called atria and the lower chambers are called the ventricles. Deoxygenated blood enters the heart at the right atrium via the superior vena cava (vein), then travels into the right ventricle which pumps the blood out to the lungs via the pulmonary trunk (artery). After oxygenation, the blood travels back to heart via the pulmonary veins and enters the left atrium. Lastly, the blood enters the left ventricle which pumps the blood out to the body via the aorta, which is the largest artery in the body.