ECPI Anatomy and Physiology (A&P) Exam 1 Practice Test

Hematopoiesis happens in red bone marrow, a tissue that resides inside bone and produces all blood cells. In adults, red marrow is found in the spaces of cancellous (spongy) bone within the medullary cavities of certain bones. The marrow itself is the active site where blood cells are formed, while compact bone provides the hard outer shell, and periosteum is the outer covering. Spongy bone simply houses the marrow within its lattice, but the actual site of hematopoiesis is the bone marrow.