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.
1 When the left ventricle contracts, the aortic valve opens. This allows blood to flow out of the left ventricle and into the aorta.  When the heart relaxes between contractions, the aortic valve closes. This prevents blood in the aorta from returning to the left ventricle.