The cardiovascular system of the model has 656 parts: a heart in 23 parts, 26 coronary vessels, 369 arteries, 177 veins and 61 pulmonary vessels. The longest single vessel is the great saphenous vein, which runs 82.2 cm up each leg of this body. Tap any part for its name and its size.
The cardiovascular system in 6 groups
| Group | Parts | What it holds |
|---|---|---|
| Heart | 23 | The 4 chambers, the walls, the valve leaflets and the papillary muscles |
| Coronary vessels | 26 | The arteries and veins of the heart's own wall |
| Arteries | 369 | The aorta and its branches to the head, trunk, arms and legs |
| Veins | 177 | The veins that return blood to the heart, among them the saphenous and cephalic veins |
| Pulmonary arteries | 33 | The vessels from the right ventricle into both lungs |
| Pulmonary veins | 28 | The vessels from the lungs back to the left atrium |
Arteries are drawn red and veins blue. The pulmonary vessels reverse the colors: the pulmonary arteries are blue and the pulmonary veins red. Each of the 6 groups has its own switch beside the model, so the veins can be hidden to leave the arteries alone.
How the heart is built
The heart is a muscular pump with 4 chambers, and the National Cancer Institute gives its size and shape as those of a closed fist. Its wall has 3 layers: the epicardium on the outside, the myocardium, which is the muscle, and the endocardium on the inside. About two-thirds of its mass lies to the left of the midline.
| Valve | Where it sits | In the model |
|---|---|---|
| Tricuspid valve | Between the right atrium and the right ventricle | 3 leaflets: anterior, posterior and septal |
| Mitral valve | Between the left atrium and the left ventricle | 2 leaflets: anterior and posterior |
| Pulmonary valve | Between the right ventricle and the pulmonary trunk | 3 cusps |
| Aortic valve | Between the left ventricle and the aorta | 3 cusps |
The heart sets its own pace. The sinoatrial node starts an impulse 70 to 80 times a minute without any signal from a nerve, and one cardiac cycle lasts 0.8 second at a normal heart rate. Hide the walls of the ventricles in the model to see the valve leaflets and the papillary muscles inside.
Arteries, capillaries and veins
There are 3 types of blood vessel. Arteries carry blood away from the heart, capillaries exchange nutrients and waste with the tissue, and veins carry blood back to the heart. The aorta has 3 portions: the ascending aorta, the arch and the descending aorta. The descending aorta of the model is 33.5 cm long.
Blood travels in 2 circuits. The pulmonary circuit runs from the right ventricle to the lungs and back to the left atrium. The systemic circuit runs from the left ventricle to the rest of the body and back to the right atrium.
To follow one vessel, type its name into the search box, pick it and press Fade the rest. The vessel stays solid while the body turns to glass around it.
What the model leaves out
The model has no capillaries, which the National Cancer Institute calls the smallest and most numerous of the vessels. Many of the smaller arteries and veins carry a name and a size only, with no written description. The vessels are those of one adult man, and their course differs from person to person.
The 3D anatomy view shows the heart together with the other organs, and the 3D respiratory system shows the airways that the pulmonary vessels follow into the lungs. The spleen, which filters blood, is in the 3D lymphatic system.