 Gill capillaries are quite small and abundant, which creates an increased surface area that water can come into contact with, thus resulting in enhanced diffusion of oxygen into the blood.Somr evidence indicates that lamellae and vessels within the lamellae on the gills contract to aid in propelling blood through the capillaries.The octopus has three hearts, one main two-chambered heart charged with sending oxygenated blood to the body and two smaller branchial hearts, one next to each set of gills.