01 / Location & anatomical relationships
In spaces inside many bones.
02 / Structure & organization
Red marrow contains hematopoietic cells within a supporting vascular environment. Yellow marrow contains a larger fat component. Distribution changes with age, with adult active marrow concentrated particularly in parts of the axial skeleton and proximal long bones.
03 / Function
Red marrow makes blood cells.
04 / Mechanism
Blood-forming stem cells in red marrow give rise to red cells, many white cells and platelets. Yellow marrow contains more stored fat. The proportions and locations change as a child grows.
Working together: skeletal system
Bones provide a framework. Muscles pull on them through tendons, and joints allow movement.
Meet this body system →Working together: lymphatic & immune systems
Lymph vessels collect extra fluid from tissues. Lymph nodes filter that fluid, and immune cells help recognize and respond to germs.
Meet this body system →FOR DEEPER STUDY
Connect structure with function
Blood-cell production includes red cells, several white-cell lineages and platelet-forming megakaryocytes. Marrow is a tissue within bone spaces, distinct from mineralized bone itself.
Check your understanding
Locate the bone marrow in relation to its neighbors. Explain how the structural features described above support its function, then distinguish it from a nearby structure with a different role.
Keep learning
Continue with OpenStax Anatomy and Physiology for system-level study. This atlas is educational and has not undergone independent medical peer review.