Final answer:
The spaces within cancellous bone contain red marrow, which is responsible for hematopoiesis, the production of blood cells occurring within the red marrow of bones.
Step-by-step explanation:
The spaces within cancellous bone contain red marrow, which is responsible for hematopoiesis. Hematopoiesis is the vital process of the production of blood cells, such as red blood cells, white blood cells, and platelets. This process takes place in the red marrow found within the cavities of certain bones, like the pelvis, ribs, and vertebrae.
Spongy, or cancellous, bone is characterized by a lattice-like network of matrix spikes called trabeculae. Within the spaces of these trabeculae, red marrow is protected and supported in its essential function of hematopoiesis. The liver and spleen can also contribute to this process by extramedullary hematopoiesis when needed, such as in cases where bone marrow function is compromised.