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.
Oxygenated blood returns to the left atrium via four pulmonary veins. It travels through the mitral (bicuspid) valve into the left ventricle. During ventricular contraction, the blood from this chamber exits through the aortic semilunar valve into the aorta and out to the systemic circulation (Fig. 22-4). Key Concept The pulmonary arteries are the only arteries in the body that carry deoxygenated blood.