The heart is a large, muscular, hollow organ with a weight of approximately 300 grams. Its function is to keep the blood moving by rhythmic activity.
The Human 3D software features the heart anatomy diagram as well as interactive heart pictures.
This hollow muscle is built in such a way that, during the contraction of the chambers (systole), the blood is pushed into the large arteries of the general circulatory and the pulmonary systems, while simultaneously it draws the blood from the veins into the auricles.
During the subsequent relaxation of the chambers (diastole), the cardiac ventricles fill up again with blood from the auricles. The heart and the vessels form the cardiac circulatory system or blood circulation, which supplies all cells of the organism with vital substances, at the same time removing waste products.
In shape, the heart can be compared with a cone lying on its side. It is located in the center of the thoracic cavity and is completely surrounded by the lungs.
Two thirds are situated in the left and one third in the right half of the thoracic cavity. The inner lining of the heart consist of a thin layer (endocardium), continued on the outside by a muscular layer (myocardium) which performs the functions of the heart. The heart is surrounded by the double-walled heart sac (pericardium).
The heart sac allows the heart to move smoothly within the thoracic cavity and prevents a straining of the cardiac wall. In its interior, the heart is divided by a membrane (septum) into what is called “right heart” and “left heart”. Each half is divided into the atrium and a heart chamber situated below the atrium, the ventricle. The heart is nourished by its own vascular system, the coronary arteries.
The heart contracts 60 to 80 times per minute each time forcing approximately 0.075 liters (0.02 gallons) of pulmonary blood from the left heart into the aorta and the same quantity of blood from the right heart into the lung (venous blood). Day after day, approximately 7,000 liters (1820 gallons) without tiring!
This is made possible by a muscle type unique to the heart, with longitudinally ramifying fibers, and by its own pacemaker, the sinoatrial node, an aggregation of nerve cells the size of a pinhead in the right atrial wall.
more information about Human 3D software
