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Red Bone Marrow Vs. Yellow Bone Marrow

Oct 7, 2020

Cross section of a bone showing yellow bone marrow


Bone marrow is a vital part of your body, but why do we need it and why is it so important? Most people have heard about bone marrow transplants for conditions like leukemia, but what exactly is it and how does it make us healthy?

Bone marrow is a nutrient-dense, spongy tissue located in the cavities of bones. Bone marrow is where blood cells are produced and where stem cells are found.

There are two types of bone marrow: red and yellow bone marrow. There are some key differences between red bone marrow vs yellow bone marrow, as the two have very different functions.

What is the function of red bone marrow?

Red bone marrow is where red blood cells, platelets and white blood cells are created. Red blood cells carry oxygen to the lungs and organs. White blood cells are what strengthen our immune system and fight infections in the body. Because blood cells last anywhere from a few days up to four months depending on the type of blood cell, our body must create new blood cells all the time. Red bone marrow is what does that. Roughly 60 to 70 percent of white blood cells are produced in the red bone marrow, according to the Chronic Lymphocytic Leukemia Society.

What is the function of yellow bone marrow?


The function of yellow bone marrow is to store fat and produce red blood cells during life-threatening situations. During serious emergencies, our body can experience rapid blood loss. Yellow bone marrow essentially transforms into red bone marrow during life-threatening events to produce blood cells and keep us alive.

It also aids with the production of fat, bone and cartilage. Importantly, it helps with the storage of fats in cells, known as adipocytes, which helps provide sustenance for bones to function.

Bone marrow stays red until the age of seven. As we age, about half of red bone marrow is slowly replaced by yellow bone marrow. Adults have an average of 5.7 pounds of red bone marrow.

Where is yellow bone marrow found?

Yellow bone marrow is located in the hollow cavity of long bones. It is typically found at the center surrounded by red bone marrow.

Where is red bone marrow found?

Red bone marrow can be found in the cavities of long bones, but is also found in the shoulder blades, hips, skull and flat bones.

Red vs. Yellow Bone Marrow: Quick Facts

  • At birth, all bone marrow is red.
  • Half of it is converted to yellow marrow by age seven.
  • Marrow produces all types of blood cells and is where stem cells are found.
  • It is essential for the body to function correctly.
  • It carries oxygen to the organs and helps prevent infections.
  • Marrow produces 200 billion new blood cells daily.
  • Adults have about six pounds.
  • During emergencies the body converts yellow bone marrow to red to help keep us alive.
  • Yellow marrow is found only in the long bones.
  • Nearly 100,000 bone marrow transplants are conducted every year.

Unhealthy Marrow

There are many things you can do to take care of your bones. Healthy bone marrow and blood cells are necessary to live. Some people are affected by diseases that cause the bone marrow to function improperly and no longer produce healthy blood cells.

Testing is necessary to diagnose conditions that affect the bone marrow, such as blood cancers like leukemia and lymphoma, or sickle cell anemia. About 10,000 people in the U.S. are diagnosed each year with diseases that require bone marrow transplants.

Testing can include aspiration. A hollow needle is inserted into the hip to remove about one milliliter of liquid bone marrow to be examined via microscope. A biopsy uses a larger needle to remove a solid core of bone tissue for examinations.

When disease is detected, a bone marrow transplant may be a necessary treatment option. During a transplant, healthy bone marrow is given to a patient via a central line. This can replace bone marrow that has lost the ability to function or has been destroyed after chemotherapy or radiation treatment. It can also help to repair the immune system to fight some cancers, like leukemia.

Medical professionals specializing in diseases of the blood can help determine if you should be screened for conditions affecting the marrow.