Last Updated on October 20, 2025 by
Red bone marrow, also known as ‘medulla rubra ossis,’ is a jelly-like tissue. It’s found in the cavities of bones. It’s key for making red and white blood cells and platelets. Knowing where it is and what it does helps us understand blood issues.
Zaynah Ahmed’s story shows how vital it is to know about blood conditions. We’ll see how red bone marrow is essential for blood cell production. We’ll also look at how its location changes as we grow. For more on blood cell production, check out Liv Hospital’s page on hematopoietic stem.
Key Takeaways
- Red bone marrow is responsible for producing red and white blood cells and platelets.
- There are two types of bone marrow: red marrow and yellow marrow.
- Red marrow is active in making blood cells, while yellow marrow is mostly fat and less active.
- Red marrow turns into yellow marrow as we age.
- Yellow marrow is typically found in long bones like the femur and humerus.
The Fundamental Role of Bone Marrow

Bone marrow is a vital tissue inside our bones. It’s key for our health. This complex organ helps produce blood cells and keeps us healthy.
Definition and Medical Terminology
Bone marrow is found in bones like the hips and thighbones. It makes blood cells. There are two types: red bone marrow and yellow bone marrow.
Red bone marrow makes red blood cells, white blood cells, and platelets. Yellow bone marrow stores fat and energy.
In medical terms, “myeloid” means bone marrow. Conditions like myeloma affect plasma cells in the bone marrow. This shows how important bone marrow is for our health, as seen in Matthew Padley’s story.
Critical Functions in the Human Body
Bone marrow has key roles in our body. Its main job is hematopoiesis, making blood cells. Red bone marrow makes:
- Red blood cells, carrying oxygen
- White blood cells, important for the immune system
- Platelets, needed for blood clotting
Yellow bone marrow stores fat but can turn into red marrow when needed. This helps our body make blood cells when it’s stressed.
Bone marrow’s role in health and disease is huge. Knowing about red and yellow bone marrow helps us understand its importance for our health.
| Type of Bone Marrow | Primary Function | Characteristics |
|---|---|---|
| Red Bone Marrow | Hematopoiesis | Produces red blood cells, white blood cells, and platelets |
| Yellow Bone Marrow | Energy Storage | Primarily composed of fat cells; can convert to red marrow under stress |
Anatomy and Structure of Bone Marrow

To understand bone marrow’s importance, we must look at its structure. It’s found inside bones, mainly in the medullary cavity and spongy bone areas. Knowing its anatomy helps us see its role in our bodies.
Macroscopic Appearance and Texture
Bone marrow is soft and spongy, found in bone cavities. It has two types: red bone marrow for making blood cells, and yellow bone marrow full of fat. Red marrow is in the spongy bone of the pelvis, vertebrae, and long bone ends.
The look of bone marrow changes based on its location and the mix of red and yellow marrow. In adults, red marrow is mostly in flat bones and long bone ends, like the proximal ends of the humerus and femur. Its soft, gelatinous texture supports a network of blood vessels and cells.
Microscopic Structure and Organization
Under a microscope, bone marrow is complex. It has a network of reticular cells and fibers that help blood cells grow. The hematopoietic cells in red marrow make blood through hematopoiesis. It has a rich blood supply, with sinusoids that let blood cells move into the blood.
- The marrow is supported by a network of reticular fibers.
- Hematopoietic cells are found in various stages of development.
- The presence of sinusoids facilitates the release of mature blood cells into the bloodstream.
Knowing the tiny details of bone marrow is key to understanding its role. Its complex structure lets it efficiently make blood cells and support the immune system.
Where Is Red Bone Marrow Found in the Human Body?
Red bone marrow is key in making blood cells. In kids, it fills almost all bones. But, as we get older, it changes. By adulthood, it’s mainly in bones like the pelvis, sternum, ribs, vertebrae, clavicles, and cranial bones. It’s also found in the top parts of long bones.
Red marrow makes blood cells, unlike yellow marrow which is mostly fat. As we age, some red marrow turns into yellow. This can make it harder for our bodies to make blood cells. Knowing where red bone marrow is and what it does is very important for our health.
To learn more about hematopoietic stem cells and blood cell production, we can dive into the bone marrow’s world. This shows how vital red bone marrow is for keeping our blood healthy throughout our lives.
FAQ
What are the two types of bone marrow?
There are two types of bone marrow: red and yellow. Red bone marrow makes blood cells. Yellow bone marrow stores fat.
Where is red bone marrow located in the human body?
Red bone marrow is in the spongy bones. It’s in the hips, vertebrae, sternum, and ribs. Kids also have it in their long bones.
What is the difference between red marrow and yellow marrow?
Red marrow makes blood cells. Yellow marrow stores fat. Yellow marrow can turn into red marrow when needed.
Where is red bone marrow found in adults?
Adults have red bone marrow in flat bones. This includes the hips, vertebrae, sternum, and ribs. It’s also in the ends of long bones.
What is the function of red bone marrow?
Red bone marrow makes blood cells. These cells are vital for our health.
How does the location of red bone marrow change from childhood to adulthood?
Kids have red bone marrow in long bones. Adults have it in flat bones and the ends of long bones.
What is yellow bone marrow?
Yellow bone marrow stores fat. It can turn into red marrow when needed. It’s in the shafts of long bones.
What is the medical term for bone marrow cells?
Bone marrow cells are also called hematopoietic cells. They make blood cells.
In which bones can bone marrow be found?
Bone marrow is in the spongy bones. It’s in the hips, vertebrae, sternum, ribs, and the ends of long bones.
FAQ
What are the two types of bone marrow?
There are two types of bone marrow: red and yellow. Red bone marrow makes blood cells. Yellow bone marrow stores fat.
Where is red bone marrow located in the human body?
Red bone marrow is in the spongy bones. It’s in the hips, vertebrae, sternum, and ribs. Kids also have it in their long bones.
What is the difference between red marrow and yellow marrow?
Red marrow makes blood cells. Yellow marrow stores fat. Yellow marrow can turn into red marrow when needed.
Where is red bone marrow found in adults?
Adults have red bone marrow in flat bones. This includes the hips, vertebrae, sternum, and ribs. It’s also in the ends of long bones.
What is the function of red bone marrow?
Red bone marrow makes blood cells. These cells are vital for our health.
How does the location of red bone marrow change from childhood to adulthood?
Kids have red bone marrow in long bones. Adults have it in flat bones and the ends of long bones.
What is yellow bone marrow?
Yellow bone marrow stores fat. It can turn into red marrow when needed. It’s in the shafts of long bones.
What is the medical term for bone marrow cells?
Bone marrow cells are also called hematopoietic cells. They make blood cells.