And these arteries always carry blood away from the ventricle of the heart and to the organs, the tissues and the cells of our body. Now let's take a look at the following diagram. So we have the heart and we also have the surrounding vessels, blood vessels. Now let's focus in on the left ventricle. The left ventricle contains a very thick layer of muscle and that is shown in black. So we have the thickest layer of muscle within the left ventricle as shown.