and white blood cells and platelets , which make whole blood. The color of red bone marrow is the result of red blood cell production. What are the two types of bone marrow? There are two types of bone marrow in your body, which are characterized by their color. Your body holds just under 6 lbs. (about 2.5 kg.) of red and yellow bone marrow. Red : Red bone marrow produces blood cells ( hematopoiesis ). Stem cells in your red bone marrow (hematopoietic stem cells) create red and white blood cells and platelets, all of which are components of your whole blood. Yellow : Yellow bone marrow stores fat. There are two types of stem cells in yellow bone marrow (adipocytes and mesenchymal stem cells). These cells preserve fat for energy production and develop bone, cartilage , muscles and fat cells for your body. Red bone marrow makes up all of your bone marrow until about age seven. Yellow bone marrow gradually replaces red bone marrow as you age. What is bone marrow made of? Bone marrow is made of stem cells. These stem cells make red bone marrow, which creates blood cells and platelets for your blood. Yellow bone marrow consists mostly of fat and stem cells that produce bone and cartilage in your body. Conditions and Disorders What are common conditions and disorders that affect bone marrow? Directly targeting bone marrow is leukemia, which is a blood and bone marrow cancer. Leukemia forms when a cell mutation occurs in your bone marrow and mutated cells multiply out of control, reducing the production of healthy, normal cells. Since bone marrow is the foundation for the creation of blood cells, blood-related conditions often are the result of abnormally functioning bone marrow. These conditions include: Multiple myeloma : Your body produces cancerous plasma cells in your bone marrow. Aplastic anemia : Your bone marrow doesn’t produce enough blood cells. Polycythemia vera : Your body makes too many red blood cells, which causes your blood to thicken. Myelodysplastic syndr

Blood - Erythropoiesis, Hemoglobin, Oxygen | Britannica ⚽️ Get Our World Cup Newsletter: The Pitch ⚽️ Learn More ## Production of red blood cells (erythropoiesis) # Blood components Ask Anything Homework Help Written by Robert S. Schwartz All Fact-checked by Britannica Editors Last updated May 25, 2026 • History Britannica AI Ask Anything Table of Contents Table of Contents Ask Anything Red cells are produced continuously in the marrow of certain bones. As stated above, in adults the principal sites of red cell production, called erythropoiesis, are the marrow spaces of the vertebrae, ribs, breastbone, and pelvis. Within the bone marrow the red cell is derived from a primitive precursor, or erythroblast, a nucleated cell in which there is no hemoglobin. Proliferation occurs as a result of several successive cell divisions. During maturation, hemoglobin appears in the cell, and the nucleus becomes progressively smaller. After a few days the cell loses its nucleus and is t