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Gray's Anatomy illustration of cells in bone marrow.

Bone marrow (or medulla ossea) is the soft tissue found in the hollow interior of bones. In adults, marrow in large bones produces new blood cells. It constitutes 4%^[1] of total body weight, i.e. approximately 2.6 kg (5.7 lbs.) in adults. Image File history File links Question_book-3. ... Dir en grey is a Japanese band formed in 1997 and currently signed to Firewall Div. ... Alternate cover Limited edition The Marrow of a Bone is an album released by Dir en grey on February 7, 2007 in Japan and in Europe[1][2] and North America[3] in the following months. ... Image File history File links Gray72. ... Image File history File links Gray72. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body (or Grays Anatomy as it has more commonly become known) is an anatomy textbook widely regarded as a classic work on human anatomy. ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... This article is about the skeletal organs. ... A blood cell is any cell of any type normally found in blood. ...

Anatomy

Marrow types

There are two types of bone marrow: red marrow (consisting mainly of myeloid tissue) and yellow marrow (consisting mainly of fat cells). Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow. Types of connective tissue Adipose tissue is an anatomical term for loose connective tissue composed of adipocytes. ... “Red cell” redirects here. ... A 250 ml bag of newly collected platelets. ... White Blood Cells redirects here. ...

Both types of bone marrow contain numerous blood vessels and capillaries.

At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type. About half of the bone marrow is red. ^[1] Red marrow is found mainly in the flat bones, such as the hip bone, breast bone, skull, ribs, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the proximal ends of the long bones femur and humerus. Yellow marrow is found in the hollow interior of the middle portion of long bones. Flat Bones. ... The pelvis (pl. ... The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... For other uses of Skull, see Skull (disambiguation). ... The human rib cage. ... A diagram of a thoracic vertebra. ... In anatomy, the scapula, or shoulder blade, is the bone that connects the humerus (arm bone) with the clavicle (collar bone). ... Cancellous is a type of cancer in the bone. ... In sciences dealing with the anatomy of animals, precise anatomical terms of location are necessary for a variety of reasons. ... The long bones are those that are longer than they are wide, and grow primarily by elongation of the diaphysis, with an epiphysis at the ends of the growing bone. ... The femur or thigh bone is the longest, most voluminous, and strongest bone of the mammalian bodies. ... The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ...

In cases of severe blood loss, the body can convert yellow marrow back to red marrow in order to increase blood cell production.

Stroma

The stroma of the bone marrow is all tissue that isn't directly involved in the primary function of hematopoiesis. The yellow bone marrow belongs here, and makes the majority of the bone marrow stroma, in addition to stromal cells located in the red bone marrow. Stroma can refer to: The connective supportive framework of a biological cell, tissue, or organ. ... Haematopoiesis is the formation of blood cellular components. ...

Still, the stroma is indirectly involved in hematopoiesis, since it provides the hematopoietic microenvironment that facilitates hematopoiesis by the parenchymal cells. For instance, they generate colony stimulating factors, affecting hematopoiesis. Parenchyma is a term used to describe a bulk of a substance. ... Haematopoiesis is the formation of blood cellular components. ...

Cells that constitute the bone marrow stroma are:

• fibroblasts (reticular connective tissue)
• macrophages
• adipocytes
• osteoblasts
• blood vessels (sinusoid)

Macrophages contribute especially to red blood cell production. They deliver iron for hemoglobin-production. A fibroblast is a cell that makes the structural fibers and ground substance of connective tissue. ... Reticular connective tissue are a network of reticular fibers (fine collagen) that form a soft skeleton (stroma) to support the lymphoid organs (lymph nodes, bone marrow, and spleen. ... Macrophages (Greek: big eaters) are cells found in tissues that are responsible for phagocytosis of pathogens, dead cells and cellular debris. ... Adipose tissue is an anatomical term for loose connective tissue composed of energy in the form of fat, although it also cushions and insulates the body. ... An osteoblast (from the Greek words for bone and to build) is a mononucleate cell that produces a protein that produces osteoid. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... “Red cell” redirects here. ... Structure of hemoglobin. ...

Bone marrow barrier

The blood vessels constitute a barrier, inhibiting immature blood cells from leaving the bone marrow. Only mature blood cells contain the membrane proteins required to attach to and pass the blood vessel endothelium. A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ...

Hematopoietic stem cells may also cross the bone marrow barrier, and may thus be harvested from blood. Sketch of bone marrow and its cells Pluripotential hemopoietic stem cells (PHSCs) are stem cells found in the bone marrow. ...

Stem cells

Main article: Mesenchymal stem cell

The bone marrow stroma contain mesenchymal stem cells (also called marrow stromal cells). These cells are multipotent stem cells that can differentiate into a variety of cell types. Cell types that MSCs have been shown to differentiate into in vitro or in vivo include osteoblasts, chondrocytes, myocytes, adipocytes, and, as described lately, beta-pancreatic islets cells. They can also transdifferentiate into neuronal cells. Mesenchymal stem cells or marrow stromal cells (MSC), are stem cells that can differentiate into osteoblasts, chondrocytes, myocytes, adipocytes, neuronal cells, and, as described lately, into beta-pancreatic islets cells. ... Multipotent stem cells can give rise to several other cell types, but those types are limited in number. ... Mouse embryonic stem cells with fluorescent marker. ... Embryonic stem cells differentiate into cells in various body organs. ... In vitro (Latin: within the glass) refers to the technique of performing a given experiment in a test tube, or, generally, in a controlled environment outside a living organism. ... In vivo (Latin for (with)in the living). ... An osteoblast (from the Greek words for bone and germ or embryonic) is a mononucleate cell that is responsible for bone formation. ... Chondrocytes (< Greek chondros cartilage + kytos cell) are the only cells found in cartilage. ... Myocyte is the technical term for a muscle cell. ... Adipocytes are the cells that primarily compose adipose tissue, specialized in storing energy as fat. ... Beta cells are a type of cell in the pancreas in areas called the islets of Langerhans. ... This article is about cells in the nervous system. ...

Compartmentalization

There is biologic compartmentalization in the bone marrow, in that certain cell types tend to aggregate in specific areas. For instance, erythrocytes, macrophages and their precursors tend to gather around blood vessels, while granulocytes gather at the borders of the bone marrow. Human red blood cells Red blood cells are the most common type of blood cell and are the vertebrate bodys principal means of delivering oxygen to body tissues via the blood. ... Macrophages (Greek: big eaters) are cells found in tissues that are responsible for phagocytosis of pathogens, dead cells and cellular debris. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Granulocytes are a category of white blood cells, characterised by the fact that all types have differently staining granules in their cytoplasm on light microscopy. ...

Types of stem cells

Bone marrow contains three types of stem cells:^[2] Mouse embryonic stem cells with fluorescent marker. ...

• Hematopoietic stem cells give rise to the three classes of blood cells that are found in the circulation: white blood cells (leukocytes), red blood cells (erythrocytes), and platelets (thrombocytes).
• Mesenchymal stem cells are found arrayed around the central sinus in the bone marrow. They have the capability to differentiate into osteoblasts, chondrocytes, myocytes, and many other types of cells. They also function as "gatekeeper" cells of the bone marrow.
• Endothelial stem cells

Sketch of bone marrow and its cells Pluripotential hemopoietic stem cells (PHSCs) are stem cells found in the bone marrow. ... White Blood Cells redirects here. ... “Red cell” redirects here. ... A 250 ml bag of newly collected platelets. ... Mesenchymal stem cells or marrow stromal cells (MSC), are stem cells that can differentiate into osteoblasts, chondrocytes, myocytes, adipocytes, neuronal cells, and, as described lately, into beta-pancreatic islets cells. ... An osteoblast (from the Greek words for bone and to build) is a mononucleate cell that produces a protein that produces osteoid. ... Chondrocytes are the cells of cartilage. ... Myocyte is the technical term for a muscle cell. ...

Diseases involving the bone marrow

The normal bone marrow architecture can be displaced by malignancies or infections such as tuberculosis, leading to a decrease in the production of blood cells and blood platelets. In addition, cancers of the hematologic progenitor cells in the bone marrow can arise; these are the leukemias. Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Tuberculosis (abbreviated as TB for tubercle bacillus or Tuberculosis) is a common and deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis. ... Leukemia or leukaemia (Greek leukos λευκός, white; aima αίμα, blood) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ...

To diagnose diseases involving the bone marrow, a bone marrow aspiration is sometimes performed. This typically involves using a hollow needle to acquire a sample of red bone marrow from the crest of the ilium under general or local anesthesia. The average number of cells in a leg bone is about 440,000,000,000. Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called a trephine biopsy) and bone marrow aspiration. ... Human male pelvis, viewed from front Human female pelvis, viewed from front The pelvis is the bony structure located at the base of the spine (properly known as the caudal end). ... It has been suggested that this article or section be merged with local anesthetic. ...

Exposure to radiation or chemotherapy will kill many of the rapidly dividing cells of the bone marrow and will therefore result in a depressed immune system. Many of the symptoms of radiation sickness are due to damage to the bone marrow cells. Radiation hazard symbol. ... Chemotherapy, in its most general sense, refers to treatment of disease by chemicals that kill cells, specifically those of micro-organisms or cancer. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... Radiation poisoning, also called radiation sickness or a creeping dose, is a form of damage to organ tissue due to excessive exposure to ionizing radiation. ...

Examination

Main article: Bone marrow examination

A Wright's stained bone marrow aspirate smear from a patient with leukemia.

Bone marrow examination is the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number of conditions, including leukemia, multiple myeloma, anemia, and pancytopenia. The bone marrow produces the cellular elements of the blood, including platelets, red blood cells and white blood cells. While much information can be gleaned by testing the blood itself (drawn from a vein by phlebotomy), it is sometimes necessary to examine the source of the blood cells in the bone marrow to obtain more information on hematopoiesis; this is the role of bone marrow aspiration and biopsy. Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called a trephine biopsy) and bone marrow aspiration. ... Image File history File links Acute_leukemia-ALL.jpg‎ A Wrights stained bone marrow aspirate smear of patient with precursor B-cell acute lymphoblastic leukemia. ... Image File history File links Acute_leukemia-ALL.jpg‎ A Wrights stained bone marrow aspirate smear of patient with precursor B-cell acute lymphoblastic leukemia. ... Wrights stain is a technique in histology that is used to make the differences between cells visible under light microscopy. ... A renal cell carcinoma (chromophobe type) viewed on a hematoxylin & eosin stained slide Pathologist redirects here. ... Leukemia or leukaemia (Greek leukos λευκός, white; aima αίμα, blood) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ... Multiple myeloma (also known as MM, myeloma, plasma cell myeloma, or as Kahlers disease after Otto Kahler) is a type of cancer of plasma cells which are immune system cells in bone marrow that produce antibodies. ... This article discusses the medical condition. ... Pancytopenia is a medical condition in which there is a reduction in the number of red and white blood cells, as well as platelets. ... For other uses, see Blood (disambiguation). ... A 250 ml bag of newly collected platelets. ... “Red cell” redirects here. ... White Blood Cells redirects here. ... Bloodletting (or blood-letting, in modern medicine referred to as phlebotomy) was a popular medical practice from antiquity up to the late 19th century, involving the withdrawal of often considerable quantities of blood from a patient in the belief that this would cure or prevent illness and disease. ... Haematopoiesis is the formation of blood cellular components. ...

Donation and transplantation of bone marrow

Main article: Hematopoietic stem cell transplantation

Bone marrow harvest

It is possible to take hematopoietic stem cells from one person and then infuse them into another person (Allogenic) or into the same person at a later time (Autologous). If donor and recipient are compatible, these infused cells will then travel to the bone marrow and initiate blood cell production. Hematopoietic stem cell transplantation (HSCT), of cells either derived from the bone marrow or peripheral blood, colloquially known as bone marrow transplantation is a medical procedure in the field of hematology and oncology that involves transplantation of hematopoietic stem cells (HSC). ... Image File history File linksMetadata Download high-resolution version (2000x1312, 1167 KB) A bone marrow harvest. ... Image File history File linksMetadata Download high-resolution version (2000x1312, 1167 KB) A bone marrow harvest. ...

Transplantation from one person to another is performed in severe cases of disease of the bone marrow. The patient's marrow is first killed off with drugs or radiation, and then the new stem cells are introduced.

Before radiation therapy or chemotherapy in cases of cancer, some of the patient's hematopoietic stem cells are sometimes harvested and later infused back when the therapy is finished to restore the immune system. Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ...

Harvesting

The stem cells are harvested directly from the red marrow in the crest of the ilium, usually under general anesthesia. Contrary to popular belief, it is a minimally invasive outpatient procedure with only minor discomfort. Another option is to administer certain drugs that stimulate the release of stem cells from the bone marrow into circulating blood. An IV is inserted into the donor's arm, and the stem cells are filtered out of the blood. The procedure is similar to donating blood or platelets. Human male pelvis, viewed from front Human female pelvis, viewed from front The pelvis is the bony structure located at the base of the spine (properly known as the caudal end). ... This article or section may be confusing for some readers, and should be edited to be clearer. ...

It may also be taken from the sternum. The tibia may seem a good source, since it is very superficial. However, except in children, this bone marrow doesn't contain any substantial amount of red bone marrow, but rather only yellow bone marrow. ^[1] The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... This article is about the vertebrate bone. ...

In newborns, stem cells may be retrieved from the umbilical cord. In placental mammals, the umbilical cord is a tube that connects a developing embryo or fetus to the placenta. ...

Bone marrow as a food

Though once used in various preparations, including pemmican, bone marrow for human consumption in America has recently fallen out of favor as a food. Now, it is commonly used only as a flavoring for soups and sauces, although dishes with intact bone marrow can still be found in some European restaurants. Bone marrow is a source of protein and high in monounsaturated fats. These fats are known to decrease LDL cholesterol levels resulting in a reduced risk of cardiovascular disease, prompting some to make bone marrow a dietary staple. The actual health effects of the addition of bone marrow to the diet remain unclear. Pemmican is a concentrated food consisting of dried pulverized beef, dried berries, and rendered fat. ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... An unsaturated fat is a fat or fatty acid in which there are one or more double bonds in the fatty acid chain. ... Low-density lipoprotein (LDL) refers to a class and range of lipoprotein particles, varying somewhat in their size and contents, which carry cholesterol in the blood and around the body, for use by various cells. ... Cholesterol is a sterol (a combination steroid and alcohol). ... Cardiovascular disease refers to the class of diseases that involve the heart or blood vessels (arteries and veins). ... In nutrition, the diet is the sum of food consumed by a person or other organism. ... A staple food is a food that forms the basis of a traditional diet. ...

References

1. ^ ^{a b c} Semester 4 medical lectures at Uppsala University 2008 by Leif Jansson
2. ^ Raphael Rubin and David S. Strayer (2007). Rubin's Pathology: Clinicopathologic Foundations of Medicine. Lippincott Williams & Wilkins, 90. ISBN 0781795168. 

See also

• Leukemia
• Bone marrow transplant
• Bone marrow examination
• Aplastic anemia
• Osso buco
• John Raymond Hobbs (Professor)

Leukemia or leukaemia (Greek leukos λευκός, white; aima αίμα, blood) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ... Bone marrow transplantation or hematopoietic stem cell transplantation (HSCT) is a medical procedure in the field of hematology and oncology that involves transplantation of hematopoietic stem cells (HSC). ... Bone marrow examination refers to the pathologic analysis of samples of bone marrow obtained by bone marrow biopsy (often called a trephine biopsy) and bone marrow aspiration. ... Aplastic anemia is a condition where bone marrow does not produce sufficient new cells to replenish blood cells. ... Osso buco is a regional dish from Piedmont in Italy. ... John Raymond Hobbs BSc Hons, MD, BS, MRCS, DObst. ...

External links

• Bioweb at UWLAX Microscopic slides of bone marrow, with explanations
• Marrow Balls
• Tostadas de tuetano
• Asian American Donor Program
• Organ Donation Blog