From Big Medical Encyclopedia

HEMOPOIETIC BODIES (synonym: bodies of a hemopoiesis, hemopoietic bodies) — bodies which main function is formation of uniform elements of blood. Carry to the hemopoietic human organs thymus (see), marrow (see), lymph nodes (see), spleen (see). The name «hemopoietic bodies» is considerably conditional since a hemopoiesis in them, except for marrow, is carried out generally only in the antenatal period, and after the birth its intensity quickly decreases. In view of a close funkts, communication To. the lake and blood G. F. Lang (1939) suggested to combine them under the general concept «system of blood».

Morphological and funkts, properties of the hemopoietic fabric were investigated by A. A. Maximov. He proved the unitary theory of a hemopoiesis, many Russian researchers took part in development a cut. The method of cloning of cells developed Tilly and Mack-Kalloky (J. E. Till, E. A. McCulloch, 1971), allowed to specify A. A. Maximov's theory.

S. P. Botkin (1875) for the first time pointed to a role of a spleen in deposition of blood and suggested about influence of a nervous system on function K. lake. V. N. Chernigovsky and A. Ya. Yaroshevsky's works (1953), Ya. G. Uzhansky (1968), N. A. Fedorov (1976), Metcalf and Moore (D. Metcalf, M. A. of Moore, 1971) showed importance of nervous and humoral factors in regulation of activity To. lake. In 1927 M. I. Arinkin offered a method of a puncture of a breast (see. Sternal puncture ) for an intravital research of marrow.

In the course of evolution there is a change of topography of a blood formation, complication of structure and differentiation of functions K. lake. At invertebrates who are still deprived of accurate organ localization of the hemopoietic fabric cells of a hemolymph (amoebocides) are disseminated diffuzno. The centers of a hemopoiesis having organ specifics for the first time appear in a wall of the digestive channel at the lowest vertebrata (cyclostomous, amphipneustic fishes). In these centers the basis is made by reticular fabric, there are wide capillaries (sinusoids). At cartilaginous and bony fishes forms isolated To. the lake — a spleen, appears a thymus. Centers of a hemopoiesis, hl. obr. a granulocytopoiesis, are available also in a mesonephros, interrenalny gland, gonads, an epicardium. At bone ganoids (an armor-clad pike) localization of a hemopoiesis in a bone tissue, namely in a head cavity over area IV of a ventricle is for the first time noted. At this stage of evolution the wall of a gut is not the basic any more To. lakes, however at fishes and higher classes of vertebrata in it remain the centers of a lymphocytopoiesis. At amphibians having a tail a hemopoiesis is concentrated in a spleen, the fringe region of a liver, in a mesonephros, an epicardium. At tailless amphibians To. lakes are a spleen and marrow which functions only seasonally (spring). Small accumulations limf, fabrics — primitive predecessors limf, nodes — appear in axillary and inguinal areas. Thus, at amphibiouses organ division actually hemopoietic and limf is planned, fabric, a cut becomes clearer at the following stages of evolution. At reptiles and birds a hemopoiesis concentrates in marrow; the spleen performs generally functions of a lymphocytopoiesis and deposition of blood. Waterfowl have two couples limf, nodes. Birds, unlike other vertebrata, along with a thymus have a peculiar limfoepitelialny body — a bursa of Fabricius, about a cut the origin of the B-lymphocytes which are carrying out humoral reactions of immunity is connected.

At mammals and the person the basic To. the lake becomes marrow, the system limf, nodes develops. The spleen loses function of formation of cells of a red row, granulocytes, megacaryocytes and only at some mammals { single-pass, ascigerous, insectivorous, lowest rodents) keeps the centers of an erythrocytopoiesis.

At early stages of embryonic development of the person primitive blood cells are formed in a wall of a vitelline bubble and around vessels in a mesenchyma of a body of a germ. From the 2nd to the 5th month of development by the basic To. the lake is a liver, in a cut the intravaskulyarny hemogenesis over extravascular prevails in the beginning, granulocytes, Megacaryocytes for the first time appear. A spleen as To. the lake actively functions from the 5th to the 7th month of development. In it it is carried out eritrotsito-, granulotsito-and megakariotsitopoez, limf. fabric is developed still poorly. The active lymphocytopoiesis arises in a spleen since the end of the 7th month of pre-natal development. In bookmarks limf, the nodes which are formed for 2 months of development the universal hemogenesis which disappears further takes place; the lymphocytopoiesis appears on the 11th week, but considerably accrues in the second half of pre-natal development. In the antenatal and post-natal period major importance in formation and functioning of lymphoid bodies belongs to a thymus, cover development in filo-and ontogenesis precedes education limf, nodes. Since the 5th month of development by the basic To. the lake becomes marrow.

The early children's age in all flat and long tubular bones contains red (active) marrow which after 4 years is gradually replaced with lipoblasts. By 25 years a diaphysis of tubular bones is already entirely filled with yellow (fatty) marrow, in flat bones lipoblasts borrow apprx. 50% of volume of marrowy cavities. By the time of the birth of the child the thymus is well developed, rich with lymphocytes. The structure of a spleen, limf, nodes continues to form up to 10 — 12 years. During this period the quantity limf increases in them, fabrics, are made out follicles, the structure of the capsule, trabeculas, sine, vessels is improved. The first signs of age involution of a thymus appear already at children's age, spleens and limf, nodes — after 20 — 30 years. At the same time gradual reduction of quantity of lymphocytes, growth of connecting fabric, increase in number of lipoblasts in a thymus and limf, nodes takes place up to almost full substitution of fabric of these bodies by them.

To. the lake, being characterized defined anatomo-fiziol, features, have common features of a structure. Their stroma is presented reticular fabric (see), a parenchyma — the hemopoietic cells. These bodies are rich with the elements relating to system of mononuclear phagocytes. Existence of capillaries of sinusoidny type is characteristic. In sine between endothelial cells there is time through which fabric K. the lake directly makes contact with a blood channel. Such structure provides transport of blood cells, and also receipt from blood in To. lake of humoral factors. V K. lakes contain in a large number myelin and amyelinic nerve fibrils, the encapsulated receptors are found. Close interaction of structures of these bodies provides variety of their functions. So, a stroma To. the lake, being basic fabric, * at the same time plays a role in creation of the microenvironment inducing a hemopoiesis. Elements of a stroma take part in marrow in processes of transport of iron along with erythroidal cells. It is confirmed morphologically with existence of the erythroblastic islands consisting of the reticular macrophage surrounded with erythroidal cells. In lymphoid bodies at induction of an immune response between a macrophage and the lymphocytes located around the cytoplasmatic bridges providing close intercellular contacts are found.

Marrow structurally it is also functionally closely connected with a bone tissue. In experiences of in vitro with mouse marrow the role of cells of an endosteum in regulation of a granulocytopoiesis is shown.

Marrow of the person is the main place of formation of blood cells. It contains the ground mass of stem hemopoietic cells and the erythrocytopoiesis, a granulocytopoiesis, a monocytopoiesis, a lymphocytopoiesis, megakariotsitopoez is carried out. Marrow participates in destruction of erythrocytes, a reutilization of iron, synthesis of hemoglobin, serves as the place of accumulation of reserve lipids. Thanks to existence of a large number of mononuclear phagocytes in marrow, spleen, limf, nodes it is carried out phagocytosis (see).

Spleen — the most difficult on a structure To. lake of the person. Takes part in a lymphocytopoiesis, destruction of erythrocytes, leukocytes and thrombocytes, accumulation of iron, synthesis of immunoglobulins. Its function includes also deposition of blood. Lymph nodes produce and deposit lymphocytes.

A spleen, limf, nodes and a thymus are components limf, the systems responsible for development immunity (see).

Enter this system also limf, educations on the course went. - kish. path. The central body of system of an immunogenesis is the thymus. The importance of a thymus in formation of population of the T lymphocytes (timuszavisimy) which are differentiated from marrowy predecessors and participating in cellular reactions of immunity is established. The origin of population of the B-lymphocytes (timusnezavisimy) which are carrying out humoral reactions of immunity is connected with marrow.

V K. the lake through a lymph and blood constantly occurs recirculation of lymphocytes. The adenoid tissue of a spleen and limf, nodes is presented to T - and B-lymphocytes. T lymphocytes are located in limf, nodes in a paracortical zone, in a spleen — about the central arteries. V-lymphocytes are localized in the centers of reproduction of follicles and brain tyazha limf, nodes, in peripheral departments limf, follicles of a spleen.

A certain influence on activity To. the lake is rendered by a nervous system. Importance in regulation of activity To. lakes have humoral factors among which it is most in detail studied erythropoetin (see). Data on existence are obtained leykopoetin (see), trombotsitopoetin (see), and also the humoral factors exerting the inhibiting impact on a hemogenesis.

Influence on To. the lake of such extraordinary factors as ionizing radiation, a hypoxia, chemical poisons, etc., can cause development anemias (see), leukopenias (see), thrombocytopenia (see).

See also Hemopoiesis .

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M. P. Khokhlova.