How Many Types of Bone Marrow are There?
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The spongy substance inside the body's bones, notably the hip and thigh bones, is called bone marrow. There are two types of bone marrow, including red bone marrow and yellow bone marrow. Bone marrows contain stem cells, immature cells that can develop into red blood cells, white blood cells or platelets.
Blood cells and healthy bone marrow are essential for human survival. Being well-versed with bone marrow locations in the human body is important as it helps provide the best course of treatment for the same in case of any ailments. So, read on to learn more about these in the following sections.
About Bone Marrow
The human body is a complex and fascinating system composed of various organs and tissues, each playing a vital role in maintaining overall health. One such crucial component is the bone marrow.
Bone marrow is a soft, spongy tissue found inside our bones. It serves as a dynamic factory responsible for producing different types of blood cells that are vital for our body's functioning.
The bone marrow functions like a busy production line, churning out the red blood cells, white blood cells, and platelets needed for oxygen transport, immune defence, and blood clotting.
In addition to producing blood cells, the bone marrow is a repository for vital vitamins and minerals. It contains stores of calcium, iron, and other necessary elements that are required for sustaining strong bones and proper body operation.
Bone Marrow Types
If you are wondering, how many types of bone marrow are there? Well, there are two main types of bone marrow: red bone marrow and yellow bone marrow. Each type has distinct characteristics and functions:
Red Bone Marrow
Red bone marrow, also known as myeloid tissue, is primarily the spongy tissue in your bones that produces blood cells. Red bone marrow’s location in the human body is very limited as it is only present in a small number of bones by adulthood, including the pelvis, vertebrae, ends of femur and tibia, scapula, skull and sternum, which are the primary locations for this type of bone marrow.
Red bone marrow comprises various cell types, including hematopoietic stem cells, which are responsible for the continuous production of new blood cells. These stem cells have the remarkable ability to differentiate into different types of blood cells, including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).
Functions of Red Bone Marrow
The primary function of red bone marrow is hematopoiesis, the process of producing new blood cells.
Erythropoiesis, the production of red blood cells, is one of the essential functions of red bone marrow. Red blood cells carry oxygen to tissues and organs throughout the body, ensuring their proper functioning.
Leukopoiesis, the production of white blood cells, is another critical function of red bone marrow. White blood cells play a vital role in the immune system, defending the body against infections and diseases.
Thrombopoiesis, or Platelet production, is also facilitated by the red bone marrow. Platelets are involved in blood clotting, which is essential for preventing excessive bleeding.
Yellow Bone Marrow
Yellow bone marrow, the second kind of bone marrow found in the body, gets its name from the abundant yellow fat cells. It is also known as fatty marrow and is found in the long bones.
Compared to red bone marrow, yellow bone marrow primarily comprises fat cells (adipocytes) and contains fewer hematopoietic cells. Red bone marrow eventually changes to yellow bone marrow as a person ages, especially in long bones. Fat accumulation within the bone marrow area causes this conversion to occur.
Functions of Yellow Bone Marrow
The primary function of yellow bone marrow is to store fat.
It is an energy reserve for the body and can be mobilized when needed.
The fat stored in yellow bone marrow provides insulation and cushioning to the bones, protecting them from mechanical stress.
Yellow bone marrow also contains mesenchymal stem cells, which can differentiate into various types of connective tissue cells, such as bone, cartilage, and fat cells.
A catastrophic emergency might cause our body (bodies) to lose blood quickly. Yellow bone marrow effectively transforms into red bone marrow to make blood cells and keep us alive during life-threatening situations.
Additionally, it helps with the synthesis of fat, bone and cartilage. Most of the bones in an adult human body have yellow bone marrow as it gradually replaces red bone marrow over time.
Differences between Red and Yellow Bone Marrow
These are some important distinctions between red and yellow bone marrow
| Red Bone Marrow | Yellow Bone Marrow |
| Also known as Medulla Ossium Rubra. | Also known as Medulla Ossium Flava. |
| More prevalent in infants and children | Becomes more dominant with age as red marrow is gradually replaced by yellow marrow |
| Highly vascular and rich in blood vessels and capillaries | Less vascular and contains more adipose (fat) tissue |
| Responsible for hematopoiesis (formation of blood cells) | Primarily functions as a storage site for adipose cells |
| Produces red blood cells, white blood cells, and platelets | Does not actively produce blood cells |
| Can revert to yellow marrow under certain conditions, such as severe anaemia or blood disorders | Does not typically revert back to red marrow |
Clinical Significance of Bone Marrow Types
The clinical significance of bone marrow types is crucial for diagnosing and managing various hematologic conditions. Below mentioned are some of the significance of bone marrow types.
Red Bone Marrow
Hematopoiesis: Hematopoiesis, or the process of manufacturing different types of blood cells, such as red blood cells, white blood cells, and platelets, takes place mostly in the red bone marrow. These blood cells are essential for the immune system, oxygen delivery, and blood coagulation.
Blood Disorders: Any disruption or dysfunction in red bone marrow can lead to blood disorders such as anaemia, leukaemia, or other hematologic conditions. In order to identify and treat these illnesses, it is crucial to comprehend how red bone marrow functions.
Bone Marrow Transplant: For bone marrow transplants, red bone marrow is a helpful supply, particularly for treating illnesses that impair the immune system or blood cells. It can be applied to swap unhealthy or diseased bone marrow from a compatible donor for healthy bone marrow.
Yellow Bone Marrow
Adipose Tissue Storage: Adipose (fat) tissue is predominantly stored in the yellow bone marrow. It gathers fat cells (adipocytes) and acts as the body's energy store.
Age-Related Changes: Yellow bone marrow eventually replaces red bone marrow as people age. This shift is a regular aspect of ageing and normally raises no clinical issues.
Diagnostic Imaging: In diagnostic imaging procedures like computed tomography (CT) scans and magnetic resonance imaging (MRI), yellow bone marrow is important. As a result of its higher fat content, it appears as low-density patches in these photos.
Takeaway
Every bone in the human body contains bone marrow. While yellow bone marrow is crucial for fat storage, red bone marrow is essential in the formation of blood cells. Ageing causes red bone marrow to be replaced by yellow bone marrow over time. The stem cells present in healthy bone marrow can be life-saving for those suffering from certain autoimmune illnesses and malignancies.
So, if you want to learn more about this, or have any particular questions regarding types of bone marrow and their details, then talk to our experts at HexaHealth. Besides offering consultation, we will also guide you to find the right treatment solutions.
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Frequently Asked Questions
What are the different types of bone marrow?
There are two types of bone marrow, red bone marrow and yellow bone marrow. The red bone marrow plays a crucial role in creating red and white blood cells, and the yellow bone marrow stores fat and helps to strengthen the bone.
Download AppWhat is the bone marrow location in the human body?
The soft, spongy tissue with many blood arteries found in the middle of most bones is called bone marrow. The bone marrow location in the human body is mostly the centre of the bones and has several blood vessels.
There are two types of bone marrow, including red bone marrow and yellow bone marrow. Blood stem cells found in red bone marrow can develop into red blood cells, white blood cells or platelets. The yellow bone marrow contains stem cells that can develop into cartilage, fat or bone cells and is primarily made of fat.
Can you classify bone marrow into different categories?
Yes, you can classify bone marrow into two categories — red bone marrow and yellow bone marrow. Now, these subtypes have two different yet crucial roles in the human body. Red bone marrow helps in the generation of RBCs and WBCs, and yellow bone marrow helps in the storage of fat.
How many types of bone marrow are there that exist in the human body?
There are two types of bone marrow in the human body— red bone marrow (myeloid tissue) and yellow bone marrow (fatty tissue). Both of them are crucial for the human body as they ensure you lead a healthy life.
Are there any major differences between different types of bone marrow?
Yes, there are distinctive differences between the two subtypes of bone marrows. Red bone marrow facilitates the production of white blood cells, platelets and red blood cells.
Our body constantly produces new blood cells, which the red bone marrow accomplishes. Having said that, human bodies can lose blood quickly in dire crises.
In such cases, yellow bone marrow effectively changes into red bone marrow to create blood cells and keep us alive.
What are the characteristics of each type of bone marrow?
Red bone marrow is composed of hematopoietic stem cells. These stem cells provide the cellular building blocks that an organism needs for oxygenation, coagulation and immunity.
The yellow bone marrow is haematopoietically inactive and has a higher fat content (80%). In cases of extreme blood loss or fever, yellow bone marrow can change into red bone marrow, serving primarily as a location for fat storage.
How does each type of bone marrow function in the body?
There are two types of bone marrow found in the body. While yellow bone marrow is crucial for fat storage, red bone marrow is essential in the formation of blood cells, and ageing causes red bone marrow to be replaced by yellow bone marrow.
Which type of bone marrow is responsible for producing blood cells?
The red bone marrow is responsible for producing blood cells. Blood stem cells found in red bone marrow can develop into red blood cells, white blood cells or platelets.
Is there a difference in the structure of different types of bone marrow?
Blood stem cells, which can develop into red, white or platelet cells, are found in the red bone marrow. Stem cells found in yellow bone marrow, which can develop into cartilage, fat or bone cells, are predominantly composed of fat.
How does the composition of each type of bone marrow differ?
While yellow bone marrow creates fat cells, cartilage and bones, while red bone marrow generates red blood cells, white blood cells and platelets.
Haemoglobin in red blood cells is responsible for the colour of the red bone marrow. Carotenoids in the fat droplets give the yellow bone marrow its colour.
Are there any diseases or disorders that affect specific types of bone marrow?
These are the various diseases that affect the bone marrow of the body:
Lymphoma
Immune deficiency disorders
Severe aplastic anaemia
Leukaemia
Multiple myeloma
References
All the articles on HexaHealth are supported by verified medically-recognized sources such as; peer-reviewed academic research papers, research institutions, and medical journals. Our medical reviewers also check references of the articles to prioritize accuracy and relevance. Refer to our detailed editorial policy for more information.
- Peconic Bay Medical Center. Red Bone Marrow Vs. Yellow Bone Marrow | Peconic Bay Medical Center [Internet]. www.pbmchealth.org. 2020.
- Seladi-Schulman J. What Is Bone Marrow, and What Does It Do? [Internet]. Healthline. Healthline Media; 2018.
- National Cancer Institute. NCI Dictionary of Cancer Terms [Internet]. National Cancer Institute. Cancer.gov; 2019.
Updated on : 26 June 2023
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HexaHealth Care Team
HexaHealth Care Team brings you medical content covering many important conditions, procedures falling under different medical specialities. The content published is thoroughly reviewed by our panel of qualified doctors for its accuracy and relevance.
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