Article updated on April 1, 2024
What is bone marrow?
The bone marrow is a fundamental organ for the functioning of our body, as it is involved in producing various blood elements. Specifically, it is responsible for the synthesis of white blood cells, red blood cells and platelets.
Contrary to what one might think, the bone marrow does not have a precise location but it is correct to say that it is dispersed in different areas of the organism.
It is found in the diaphyseal canal, commonly known as the medullary cavity, inherent to the central part of the long bones, and also in the cavity of the spongy tissue.
It is said that the amount of bone marrow contained within each person corresponds to approximately 4% of the total body weight, or 2.6kg if we refer to an adult of average build.
The types of bone marrow
Having said that, it is important to underline here that 2 different types of bone marrow are recognized in human anatomy: the red one and the yellow one.
The first is mainly made up of myeloid tissue, while the second is composed of adipose tissue which determines its color.
In reality we could also speak of a third typology, as well as the bone marrow gelatinous, present exclusively in elderly people.
The bone marrow is considered a vascular organ, as it contains an innumerable series of blood vessels and capillaries.
At birth and throughout most of childhood, each of us has the red bone marrow type. As the latter grows, it converts into the yellow one. It is also possible that the opposite occurs, i.e. reconversion, when for example there is a haemorrhage.
But what are the main functions of these types of marrow?
Red has the task of synthesizing the elements of the blood and is contained in the spongy bone tissue of the epiphyses of short, flat and long bones, such as the trunk, skull, jaw, etc.
The yellow marrow is made up mostly of fat and is found in the diaphysis of long bones.
The functions of the bone marrow
We have therefore understood how the bone marrow can be considered the production center of all cells which are found in the marrow itself and in the peripheral blood.
Its work fundamentally depends on the function of pluripotent stem cells. The latter term indicates the ability to diversify into many other types of cells.
Stem cells
Inside the medullary tissue There are 3 types of stem cells:
mesenchymal: they are contained in the stroma and are arranged in a row around the central sinus of the bone marrow. They constitute the embryonic tissue from which the connective tissue, blood vessels and lymphatic vessels are formed; haematopoietic: they are further divided into three classes of blood cells, found in the circulation, i.e. leukocytes, erythrocytes and thrombocytes. The process that allows the development of different blood cells, starting from these stem cells, is called hematopoiesis. From here it can be deduced that stem cells can transform into any other blood cells, based on the influence of certain tissue and hormonal factors; endothelial: make up blood vessels.
Leukocytes, erythrocytes and thrombocytes
It is necessary to include in this article a small parenthesis about the functions of the hematopoietic cellsin order to allow us to better understand the discussion in question.
It has already been mentioned that this term refers to white blood cells (leukocytes), red blood cells (erythrocytes) and platelets (thrombocytes).
Each plays a fundamental role for our organism: as regards red blood cells, it is known that they are mainly responsible for the transport of oxygen. Their production process is called erythropoiesis and lasts approximately 7 days.
It is important to underline that the life of these cells has a very specific duration, approximately 120 days, after which they are eliminated by white blood cells or macrophages.
If a lack of oxygen is felt, production is stimulated Oferythropoietin in the kidneys which, in turn, stimulate what is directly involved, i.e. the bone marrow. When the situation normalizes, the kidneys stop producing this substance, consequently stopping the production of red blood cells. This is a truly incredible mechanism.
As for the white blood cells or leukocytes, they are very important for the immune system. Also in this case it is possible to mention different types of the species, an example could be lymphocytes, which are essential for producing antibodies in the event that infections occur; or the granulocytes that intervene to fight infections, allergies or parasites.
Finally you have the platelets, produced by the marrow through a process called thrombopoiesis and essentially serve for the formation of blood clots, in case there are wounds. This means that the sudden loss of blood or an injury triggers the functioning mechanism of these cells which intervene promptly to aggregate with other substances and form fibrin.
Bone marrow examination
After having included this little in-depth analysis on hematopoietic cells, we continue the discussion on bone marrow by talking about the specific tests that can be done in relation to any pathologies.
When it comes to thebone marrow examinationreference is made to aspirate and biopsy.
Although the bone marrow produces blood cells, from which it is possible receive information through a simple withdrawal, sometimes it is useful to use one of the systems mentioned, to examine in detail the source of these cells. This is the main task of the biopsy and aspirate.
The latter can be understood as the marrow blood sampling. The procedure is not very long but is often considered painful by those who have already had the opportunity to try.
In essence, a specific needle is used, which has an adjustable stop at one end and is crossed by a mandrel.
The zone where it is possible to carry out this sampling can be: sternum, posterior and anterior illiac crest.
The biopsy, on the other hand, involves an almost similar procedure but with different instrumentation and is used to evaluate the cell density, the hematopoietic tissue and the relationship between the cells and the stroma.
Diagnosis and diseases of the bone marrow
It is clear that the bone marrow represents an organ equally subject to diseases, even serious ones: an example could be leukemia, multiple myeloma, anemia, pancytopenia and much more. Even chemotherapy can have a negative impact on it.
In the event that the doctor suspects such types, it is absolutely necessary to carry out a histological examination of a bone marrow sample taken from the individual concerned. Unfortunately, these are very delicate cases, whose timely intervention is fundamental for the person’s life.
In any case, it must also be said that the chances of survival and recovery are significantly higher than in the past. In this area, research has made giant strides and today it is even possible to carry out a transplant, in the case of more serious diseases.
Bone marrow donation and transplant
Must distinguish stem cell donation from bone marrow transplantas they are two distinct and separate situations that require, without any doubt, a different procedure.
In the event that a person needs new stem cells, they can be taken from one person and then injected into the other applicant. It is clear that in these cases the donor and the recipient must be compatible.
Stem cells can be taken directly from the bone marrow in the crest of the ilium, or from the arm, sternum and tibia, which are also considered good sources.
In Italy this procedure is regulated through the National register of voluntary donors, which is called IBMDR. It is recognized by state law.
If necessary, before the actual operation, the patient’s bone marrow can be destroyed through radiation. The actual transplant consists of taking cells from the donor and injecting them into the recipient. They migrate to the areas where tissue is normally found and begin producing blood cells.
There is even another type of procedure that can be carried out before the chemotherapy treatment: that is, the stem cells can be taken to prevent them from being damaged or destroyed by the therapy, and then reinserted at the end of the treatment. In this case we are talking about an autotransplant and also requires numerous blood transfusions.
The fundamental characteristics of the donor
It was previously mentioned that, for the donation to take place, the donor and the recipient must be compatible. Regardless of the compatibility factor which must be evaluated taking into consideration a series of factors, it is necessary to underline the fact that to be a donor one must reflect certain characteristics. This assumes the fact that not everyone can be a donor, for various reasons.
Generally, i requirements requiredthey are:
aged between 18-35 years at the time of registration in the national register; maximum age for making donations is 55 years; not be affected by blood diseases; do not use narcotic substances; not be affected by infectious diseases; do not suffer from serious chronic diseases.
The conditions just mentioned are essential so that a donation can be made that leads to a satisfactory result.
In order to become a donor, your state of health is fundamental. For this reason, prevention plays an important role, based on following small life rules that ensure the well-being of the person, such as correct physical exercise or eating healthily.
Donating bone marrow is a truly generous gesture, which can change the lives of many people. It represents hope and can really make a difference for all those who find themselves in the dramatic situation of having to face very serious illnesses.
Here you will find all the offers at low prices on Amazon