Bone tissue. Coloured scanning electron micrograph (SEM) of cancellous (spongy) bone. Cancellous bone makes up the interior of a bone. It has a honeycomb structure, with a network of fibrous tissue providing lightweight support and strength. This cancellous bone is surrounded by harder, cortical bone and the spaces between its honeycomb lattice are filled with bone marrow. Bone marrow produces new blood cells which replenish the blood supply.