The systemic circulation is the portion of the circulatory system is the network of veins, arteries and blood vessels that transports blood from heart, services the body's cells and then re-enters the heart, the Mayo Clinic noted. [Image Gallery: The BioDigital Human]
A southern pine (2) 2x12 beam can span 8 feet when supporting joists spanning a maximum of 14 feet, and it can cantilever 2 feet beyond the posts on each side. With the allowable cantilever of the joists, this beam would support a deck 12 feet by 17 1/2 feet.
A 2x8 up to 12 feet; 2x10 to 15 feet and 2x12 to 18 feet. The larger the deck, the larger the joists. In typical deck construction, with a ledger on one side of the joist and beam on the other, the size of the joists is driven by the size of the deck based on the general maximum spans mentioned above.