The left heart consists of two chambers: the left atrium and the left ventricle, which are separated by the mitral valve.[9] The left atrium receives oxygenated blood returning from the lungs through the four pulmonary veins. The left atrium has an external sinus called the left atrial appendage. As in the case of the right atrium, the left atrium is lined with the metatarsal muscles.[25] The left atrium connects to the left ventricle via the mitral valve.[9]
The left ventricle is thicker than the right ventricle because of the greater force it needs to pump blood throughout the body. As in the right ventricle, the left ventricle has carcinoid trabeculae, but it does not have a modified duct. The left ventricle pumps blood to the body through the aortic valve to the aorta and from there to the rest of the body. The heart also receives blood through two arteries that branch out from the aorta above the valve, which are the left coronary artery, which is the main one, and the right coronary artery.[9]
heart wall
