The heart and lungs are located in the thorax, or chest cavity. The heart pumps blood from the body to the lungs, where the blood is oxygenated. It then returns the blood to the heart, which pumps the freshly oxygenated blood to the rest of the body. The heart and lungs, together with the blood vessels, comprise the cardiovascular system. This system transports vital nutrients, gases, and hormones to the rest of the body.
The heart is a pear shaped organ, positioned centrally within the chest cavity, with the apex extending over to the left nipple. The heart is divided into a right and left side, each side having an atrium and ventricle. The contraction of the heart pumps blood throughout the body. The right side receives oxygen poor blood from the major veins of the body, and pumps this blood into the lungs, where it is oxygenated. The left side of the heart then receives oxygen rich blood from the lungs, and pumps this blood through the arteries, into the body.