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Bone Marrow is a soft, gelatinous tissue that fills the medullary cavities or centers of the bones. It is a spongy tissue inside some of the bones in the body, such as the hip and thigh bones. It contains immature cells called stem cells in them. There are two main types of Bone Marrow:
- Red Bone Marrow: Red bone marrow helps to produce blood cells. It is also known as myeloid tissue.
- Yellow Bone Marrow: Also known as fatty tissue, this bone marrow helps to store fats.
Both red and yellow bone marrows are enriched with blood vessels and capillaries. Bone marrow makes more than 220 billion new blood cells on an everyday basis. People with blood cancer and other life-threatening conditions rely on bone marrow or cord blood transplants to survive.
Read More: NCERT Solutions for Class 11 Biology Structural Organisation in Animals
Key Terms: Bone Marrow, Red Bone Marrow, Yellow Bone Marrow, Bone Marrow Transplant, Bones, RBCs, WBCs, Stem Cells
What is Bone Marrow?
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Bone Marrow is a soft and fatty tissue that fills the cavities of bones as bones themselves are porous from the inside.
- Bone marrow is present in the center of most bones in the human body.
- It contains fat and immature blood cells.
- Human bone marrow produces around 500 billion blood cells every day.
- It produces white blood cells, that help fight diseases and build immunity.
- It also helps in the formation of red blood cells and platelets.
- Any effect on bone marrow also affects the total counts of blood cells and may lead to fatal consequences and life-threatening diseases.
Bone Marrow
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| Types of White Blood Cells | Thalassemia | Difference between Bone and Cartilage |
| Difference Between RBC and WBC | Difference Between T cells and B Cells | Discovery of Cells |
Functions of Bone Marrow
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Bone marrow is crucial for sustaining life in living organisms. The important functions performed by bone marrow are
- The main function of bone marrow is to produce different types of cells.
- The blood vessels of bone marrow form a barrier that stops immature blood cells from leaving the marrow.
- In order to combat current diseases, the bone marrow also restores the immune system.
- It serves as a kind of valve to stop lymphatic situations from backflowing.
- Yellow bone marrow stores fat that is used as a source of energy as needed.
- B cells develop in the bone marrow, where they play a major role in mediating the creation of antibodies that are antigen-specific immunoglobulins (Ig).
Types of Bone Marrow
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There are two main types of Bone Marrow namely:
- Red Bone Marrow
- Yellow Bone Marrow
Red Bone Marrow
Red Bone Marrow forms all the blood cells and as one age it is replaced by the yellow bone marrow. They divide the blood cells to produce more new blood cells and are mainly located in long bones, ribs, shoulder blades, skull, and spine. Red bone marrow produces three types of blood cells:
- Red Blood Cells: RBCs play a vital role in the transport of oxygen in the body as they contain a complex protein called hemoglobin. The average lifespan of RBCs is 120 days.
- White Blood Cells: Also known as leukocytes, WBCs are colorless due to a lack of hemoglobin and help in fighting against infections.
- Platelets: Also known as thrombocytes, platelets help in clotting your blood.
Red and Yellow Bone Marrow
Yellow Bone Marrow
Yellow Bone Marrow helps in storing fats in the body.
- The fats stored in Yellow bone marrow are known as adipocytes.
- They have a low blood supply.
- They are located in the central cavities of long bones and can be converted into red blood cells due to excessive blood loss or fever.
Read More: Structural Organisation In Animals
Difference between Red Bone Marrow and Yellow Bone Marrow
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The difference between red bone marrow and yellow bone marrow is listed below:
| Red Bone Marrow | Yellow Bone Marrow |
|---|---|
| Red bone marrow contains blood cells and where RBCs, WBCs, and platelets are produced. | Yellow bone marrow stores fat and also produces RBCs whenever necessary. |
| Red bone marrow can be found in cavities of long bones, shoulder blades, hips, skulls, and flat bones. | Yellow bone marrow is present in the hollow cavity of long bones. |
| At birth, the entire bone marrow is red in color. | As we age red bone marrow converts into the yellow bone marrow. |
| Due to the presence of hemoglobin in red blood cells, these are known as red bone marrow. | It is yellow because of fat droplets which contain carotenoids. |
| It is surrounded by the outer surface of the bone. | It is located in the center of the red bone marrow. |
| Red bone marrow is also referred to as medulla ossium rubra. | The other name for yellow bone marrow is ossium Flava. |
Structure of Bone Marrow
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Bone marrow is a soft, flexible connective tissue that is highly vascular and therefore serves as the primary site of production of new blood cells.
- Bone Marrow is made up of both cellular and non-cellular components.
- It is divided into vascular and non-vascular regions.
- The vascular region contains blood vessels that give the bones nutrients and also transport blood stem cells away into circulation.
- The nonvascular region is composed of hematopoietic cells of various lineages and maturity packed between fat cells.
- They are thin bands of bony tissue where the production of all the cellular components of blood and plasma takes place.
Structure of Bone Marrow
Difference between Vascular and Non-Vascular Region
The difference between the vascular and non-vascular regions of bone marrow is listed below:
| Non-Vascular Section of Bone Marrow | Vascular Section of Bone Marrow |
|---|---|
| Hematopoiesis takes place in the non-vascular region which is the production of all of the cellular components of the blood and plasma. | Vascular section contains the blood vessels that supply bones with nutrients and transport the blood stem cells and formed mature blood cells away into the circulation in the body. |
| Non-vascular section is composed of hemopoietic cells of various maturity and lineages. | Vascular section fosters the hemopoietic cells cluster prior to their discharge into the bloodstream. |
Read More: Structural Organization in Animals Important Questions
Where is Bone Marrow Located?
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Bone marrow comprises 5% of the total weight of adult human beings. It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adults, bone marrow is generally located in the following areas:
- Ribs
- Vertebrae
- Sternum
- Breastbone
- Hips
- Skulls
- Ends of the long bones of arms and legs.
Bone Marrow Diseases
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The lack of proper function of bone marrow due to any reason will cause many disorders and problems in a person. Most of these problems are blood-related and immunity-related conditions.
- Fever is caused due to the lack of healthy white blood cells in the body.
- There might be weakness or fatigue even when one performs milder activities due to the lack of oxygen-carrying hemoglobin in the red blood cells.
- There will be shortness of breath due to the lack of oxygen in the blood circulation, which is caused due to the absence of hemoglobin in the red blood cells.
- One may get infected more frequently due to fewer white blood cells.
- Leukemia is a cancer of white blood cells that can decrease the production of other cells too. Patients with leukemia may have infections, bleeding, and bone and joint pain.
- Aplastic Anemia is a condition where there is a decrease in the production of red blood cells due to any injury to bone marrow or any defect in stem cells.
- Myeloproliferative Disorder (MPD) is a condition in which there is an overproduction of immature cells and is a blood cancer caused by changes in the stem cells inside the bone marrow.
- Lymphoma is a cancer that begins in lymphocytes that are fighting cells for the immune system. Cells change and grow out of control in this situation and symptoms are swollen glands, cough, fever, itching, and weight loss.
Read More: Structural Organization of Animals MCQ
Bone Marrow Transplant
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Bone Marrow transplant is needed to cure diseases like blood cancer or leukemia. In this process, the donor’s blood cells are given to or injected into the recipient's bone marrow.
- Blood cancers generally begin with genetic mutations in stem cells.
- Stem cells are not cancerous but mutations can interfere with the process of differentiation and can result in the formation of malignant blood cells.
- Allogenic bone marrow transplant transplants the patient’s bone marrow with donors.
- Blood stem cells are extracted from the donor’s blood and filtered before transporting it into the patient’s body.
- Secondly, Bone marrow is extracted directly from a bone in the hip, and iliac crest with a needle.
- It is to be further noted that high doses of chemotherapy or radiation can kill the patient’s existing bone marrow destroying both malignant and blood stem cells and also weakening the immune system.
Bone Marrow Transplant
Types of Bone Marrow Transplant
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The types of bone marrow transplants are
Autologous Bone Marrow Transplant
- A person’s own blood cells are collected in this method.
- Chemotherapy is done, high doses of chemotherapy kill cancer cells but also remove stem cells from the bone marrow.
- Afterward collected blood cells are put back into the bone marrow.
Allogeneic Bone Marrow Transplant
This transplant involves a donor who has the same genetic type as patients like a sibling, or the parent. It has two sub-divisions:
- Umbilical Cord Blood Transplant: Cord blood for transplantation is collected from the umbilical cord and placenta after a baby is delivered. That blood is stored at a blood bank for further future use
- Syngeneic Transplant: It involves getting stem cells from the identical twin.
Also Check:
| Related Topics | ||
|---|---|---|
| Difference Between Blood and Plasma | Difference Between Plasma and Serum | Body Fluids and Circulation |
| Blood Coagulation | Blood Circulatory System | Cisplatin |
Ways to Healthy Bone Marrow
The ways to maintain healthy bone marrow are as follows:
- Performing exercises that involve lifting weights and strength training.
- Getting enough vitamin D as it is critical for bone health.
- Have little sunlight for approximately 15 minutes each day and also add milk, juice, cereal, and almonds to your diet.
- Treat diseases that have abnormalities in the bone marrow as a side effect.
- Contrary to popular belief, one must avoid eating a low-calorie diet at all costs.
- Having vitamin C and vitamin K food in your diet and also consuming food with high magnesium and zinc.
- It's crucial, especially for women, to continually maintain good health and an active lifestyle so that bones don't grow brittle after menopause.
Things to Remember
- Bone Marrow is the soft and spongy substance found inside the bones.
- Hematopoietic stem cells are found in the bone marrow.
- Red blood cells, white blood cells, and platelets are produced by the bone marrow.
- 5 percent of an adult human's weight is made up of bone marrow.
- Bone marrow is classified into two major categories namely Red Bone Marrow and Yellow Bone Marrow.
- Red bone marrow produces blood cells, and yellow bone marrow stores fat in the body.
- Any effect on bone marrow would result in blood or immunity-related health conditions.
Previous Years’ Questions
- Bone marrow is absent in the bones of… (Punjab PMET 2007)
- The lining of the bone marrow cavity is called…
- Role of bone marrow in mammals is… (Chhattisgarh PMT 2004)
- Cells formed in bone marrow include… (NEET 1992)
- Yellow bone marrow is found especially in the medullary cavity… (AIIMS 1996)
- In our body, the blood bank is… (Chhattisgarh PMT 2005)
- Leucopenia is the condition where…
- T-lymphocyte is produced in… (WBJEE 2009)
- The process of formation of blood corpuscles is… (AFMC 2005)
- Total number of bones in each limb of a man is… (NEET 1998)
Sample Questions
Ques. Is bone marrow an organ? (1 Mark)
Ans. Bone marrow comes under the primary lymphoid organ but in general, it is the soft tissue that has many blood vessels.
Ques. Which blood cells are produced by bone marrow? (3 Marks)
Ans. The blood cells produced by bone marrow are
- Red Blood Cells: They are the cells that work to carry oxygen-rich blood to the cells of the body.
- Platelets: They help the blood clot and prevent uncontrolled bleeding.
- White Blood Cells: These cells work to help your body fight off infections.
Ques. Can bone marrow fill the gap between two broken bones? (1 Mark)
Ans. Bone marrow produces blood cells and cannot restore the gap of fracture but yes can help in curing that.
Ques. Where is Bone Marrow found? (3 Marks)
Ans. Bone marrow is found in the following parts of the body:
- Skull
- Vertebrae
- Sternum
- Ribs
- Ends Of The Humerus (Upper Arm Bone)
- Pelvis
- Ends Of The Femur (Thigh Bone)
- Ends Of The Tibia (Shin Bone)
Ques. How does blood leave the bone marrow? (1 Mark)
Ans. Blood cells leave bone marrow via the blood vessel system as fresh blood is transported into organs through arteries and used blood through veins is backed out of the body.
Ques. List the functions of yellow bone marrow. (3 Marks)
Ans. The functions of yellow bone marrow are:
- Yellow bone marrow helps in the storage of fats known as adipocytes. These fats are used as an energy source when needed.
- Mesenchymal stem cells are also present in the yellow bone marrow. These cells develop into bone, fat, cartilage, or muscle cells.
- Yellow bone marrow starts to replace red bone marrow over time, and most bones in an adult body contain yellow bone marrow.
Ques. How long does it take red blood cells to regenerate? (1 Mark)
Ans. Blood cells usually take four to five weeks to regenerate but the formation of new blood cells only takes about 2 days
Ques. What vitamins can help in increasing red blood cells? (1 Mark)
Ans. Vitamin B12 can help your body make more red blood cells, so you should eat food that contains Vitamin B12 such as meat, eggs, cereals, and dairy products.
Ques. What is the cost of Bone marrow transplants in India? (1 Mark)
Ans. In India, the autologous transplant can cost 8-12 lakhs and the allogenic transplant can cost 12-17 lakhs.
Ques. Name a few general conditions to occur when bone marrow is affected. (3 Marks)
Ans. When the bone marrow of our body is affected due to any reason, it may cause the following conditions:
- Fever: It is caused due to not having enough healthy white blood cells.
- Fatigue: It is caused by a lack of hemoglobin, the protein in red blood cells that carries oxygen.
- Increased Infections: Due to fewer healthy white blood cells, infections are more prone.
- Shortness of Breath: Less oxygen is delivered to tissues in the body due to fewer RBCs.
Ques. What is the success rate of bone marrow transplants? (1 Mark)
Ans. The success rate in India for allogeneic transplants is 60%-80% and70%-90% with a related match but 65% with an unrelated donor.
Ques. Can a person live without bone marrow? (2 Marks)
Ans. Bone marrow produces blood cells that contain oxygen, white blood cells that fight infections, and platelets to help your blood clot. So without it, you cannot survive and the absence of it can be proved fatal.
Ques. Does bone marrow grow back? (1 Mark)
Ans. Yes, the bone marrow does grow back as every stem blood cell is constantly dividing into new blood cells but regrowth generally takes a few weeks.
Ques. What is Bone marrow aspiration? (2 Marks)
Ans. It is the procedure in which a small sample of bone marrow is collected usually from the hip bone, and thigh bone, and used in the diagnosis of various conditions like leukemia, anemia, and blood cancer.
Ques. What happens to a body with no bone marrow? (3 Marks)
Ans. Bone marrow serves as the body's blood cell "factory," generating platelets, which aid in blood clotting when injured, white blood cells, which assist the immune system fight disease, and red blood cells, which carry oxygen throughout the body by way of the bloodstream. One is usually sick and vulnerable to several diseases if they do not have bone marrow or does not have healthy bone marrow.
Ques. What are the risks involved in Bone Marrow Transplant? (3 Marks)
Ans. The risks involved in Bone Marrow Transplant are as follows:
- Bone marrow transplant is a major medical procedure and patients can experience nausea, headache, and sometimes even vomiting.
- It can cause graft versus tumor activity in which new immune cells are generated by donated marrow which can wipe out cancer cells but the recipient’s immune system cannot work properly.
- Damage to organs and infection complications.
- Early menopause
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