An “in situ” view is one that leaves the structure in it’s original place. In the view below, the heart of the cat has been cut to reveal the left and right ventricle. Note that the left ventricle has a much thicker muscular wall. This is because it is responsible for pushing blood out the aorta which will deliver oxygenated blood to the rest of the body. The left ventricle only needs to push blood to the lungs and back through the pulmonary artery, this route is known as the pulmonary circuit.