Megakaryoblast

A megakaryoblast is a cell that is the precursor of a platelet-forming cell - a megakaryocyte. Megakaryoblast is present in the hematopoietic tissue of the bone marrow. It is formed from a hematopoietic stem cell and in the process of its maturation, bypassing the intermediate stage (promegakaryocyte), turns into a megakaryocyte. Thus, the megakaryoblast is the precursor of the megakaryocyte, responsible for the formation of platelets.

Megakaryoblast is a cell that is the precursor of megakaryocytes, which in turn produce platelets. Megakaryoblasts are formed from a hematopoietic stem cell in the bone marrow and are the initial stage of the megakaryocyte lineage.

Externally, megakaryoblasts are quite small in size and contain one or two nuclei. They possess granular cytoplasm with many organelles such as mitochondria, ribosomes, corpus coeruleus and endoplasmic reticulum.

During the process of differentiation, megakaryoblasts go through several developmental stages. The first stage is the promegakaryocyte, which undergoes further differentiation into a megakaryocyte. Ultimately, the megakaryocytes divide into thousands of fragments that become platelets.

Megakaryocytes are the largest cells in the bone marrow and have up to 64 nuclei. They contain a variety of intracellular signaling pathways and growth factors that regulate their differentiation and function.

The functions of megakaryoblasts and megakaryocytes are not limited to platelet production. They are also involved in the regulation of hemostasis, immune response and angiogenesis. Disturbances in the development and function of megakaryocytes can lead to various pathological conditions, such as thrombocytopenia, thrombosis and hemorrhagic disorders.

Thus, megakaryoblasts and megakaryocytes play an important role in hematopoiesis and maintaining the health of the body as a whole. Studying their properties and functions can lead to the development of new methods for treating various diseases associated with hemostasis disorders and thrombocytopenia.

Megakaryoblast is a precursor of platelet cells - megakaryocytes. It is found in the germ layers of organs. Precursors are distributed over different areas of the body and bone marrow; stem cells that precede the erythroid series are found in the lungs and liver, and T- and B-lymphocytes are found in the hematopoietic organs of the body. At all stages of ontogenesis, the bone marrow is the center of proliferation or differentiation of stem cells. This organ undergoes constant regeneration in the body from four years of age and older at a minimum rate of about one nucleus per minute. Bone marrow restoration significantly depends on the amount of hematopoietic precursors produced in it by stem cells. Stem cells and their differentiation play a primary role in maturation and differentiation.

Megakaryoblasts, like many other hematopoietic cells, undergo radial elongation and circulate in the blood system. They form the endothelial wall of blood vessels and settle in the area of ​​hemostasis formation and the development of the immune system. Megakaryocytes are also found in the red bone marrow and placenta of mammals.

A significant event in the study of megakaryoblasts was their description by the Russian school of hematologists. The formation of megakaryoblasts was noticeably different from that of megakarycytes and lymphoblasts, the precursors of leukocytes. Back in the 20s of the last century, A.A. Maksimov and his colleagues wrote about the abundant generation of erythroblast from megakaryotrophoblastic nodes of megaloplastic bone marrow in people with a very high hemoglobin content and that megakaryoblasts with some forms of granulocytes detected are not typical. It has been established that in the early stages of megakarocyte maturation, pronounced lymphocytosis of the blood of megacarocytes, which belong to agranulocytes, is observed.

In the literature, there have been isolated descriptions of formations of the so-called intermediate phases between megacarcioblasts and megacaricytes. But the issue of such a phase was not clarified. Only in the 50s did they receive a conclusive explanation for the microscopic and histochemical differences between megakaryoblasts and megakaryobites. For the latter, a new micromorphological characteristic was proposed: a sharp decrease in nuclear chromatin, accumulation of large nucleolemmas and terminal syzygies in the nucleus. Later, Ya.P. Denisyuk believed that chromatosis of neutrophils, eosinophils and monocytopeptide cells is a reliable sign of their erythroid content. If the first attempts to identify the connection between megakaryobablasts and their differentiated forms are known abroad, they appeared 30-40 years after the description of the new type of precursors. The question of the origin of megacarbs was resolved by American hematologists G. Mann, M. Kadel and others. The discovery made it possible to substantiate the multi-stage morphological and functional classification of mi cells