Asker's rating. 1  Fred is correct the smaller the number the bigger the metal. 2  12 gauge is thinner than 7 gauge. 3  The gague refers to the thickness of the metal in question. the issue of strenght is really determines by the type of metal, not necessarily it's thickness.
The left ventricle pumps oxygen-rich blood out of the heart and into an artery called the aorta. From the aorta, blood branches out into a series of ever smaller tube-like vessels: arteries, arterioles and finally capillaries. The capillaries deliver the blood's oxygen and nutrients to cells.
The blood from the lungs reenters the heart through the left atrium. The left atrium them pushes blood into the left ventricle, which in turn pumps the oxygenated blood throughout your body. Notice that blood always enters the heart through an atrium, and always leaves the heart through a ventricle.