Final answer:
Spongy bone or cancellous bone is found inside flat and trabecular bones and contains a network of trabeculae filled with red marrow and stem cells involved in blood cell production.
Step-by-step explanation:
Spongy tissue in flat bones and trabecular bones is known as spongy bone or cancellous bone. Unlike compact bone tissue, spongy bone tissue lacks osteons and is composed of trabeculae, which are a network of rod-like or plate-like structures. These trabeculae support the overall structure of the bone and house osteocytes within them. The spaces between trabeculae are filled with red bone marrow, which contains stem cells. These stem cells are vital for the process of hematopoiesis, where they differentiate to give rise to red blood cells, white blood cells, and platelets. Moreover, blood vessels run throughout this spongy bone tissue to provide nutrients to osteocytes and to help in the removal of waste products.