Describe The Relationship Between Atria And Ventricular Valves

The heart is a hollow muscular organ that lies within the mediasternum, a mass of tissue extending from the sternum down to the vertebral column between the lungs. Structurally, the heart is composed of three layers of tissue; epicardium, myocardium (middle layer) and endocardium (inner layer). The epicardium is a layer of muscle composed of mesothelium and connective tissue sheltering the external surfaces of the heart. This external layer is directly merged with the myocardium internally and is in contact with the serous layer of the pericardium. In some cases, it is viewed as a division of the inner layer of the pericardium, the pericardium being the membrane surrounding and protecting the heart essentially keeping the heart in its right

A set of valves are present in the interior structure of the heart to keep fluid from flowing in one direction. The heart has two types of valves that assist in keeping blood from flowing in the correct direction. Valves located between the atria and ventricles are known as atrioventricular valves (or cuspid valves), and the valves located at the bases of the large vessels leaving the ventricles are called semilunar valves (or pulmonary valve for the right side and aortic valve for the left side). Each set of valves carry out their functions so that regurgitation does not occur. For example, when the ventricles contract, atrioventricular calves close to prevent blood from flowing back into the atria. In contrast to this, when the ventricles relax, the semilunar valves close to prevent back flow into the

The oxygenated blood passes through the bicuspid valve and into the left ventricle where it will be ejected into the largest artery of the body known as the aorta via the aortic valve. The ejected blood will then be distributed throughout the body using a network of blood vessels. The distribution of blood throughout the body occurs via the four divisions of the aorta; the ascending aorta, the aortic arch, the thoracic aorta and the abdominal aorta. Beyond the aortic valve within the ascending aorta, there ate miniature openings called coronary ostia which arise from the left and right coronary arteries that supply blood to the heart