ESSAY
The topic of the disease of the spleen. Changing the organ with inflammatory and exchange diseases. Tumors and arterial hypertension spleen.
Performed: Isakov Anastasia Aleksandrovna
Group number 310
Checked D.M. Casimirova Angela Alekseevna
Chelyabinsk 2012.
Introduction 3.
Anatomy and histology of the spleen 4
Normal and pathological physiology spleen 5
Pathological anatomy of the spleen 7
Diseases of the spleen 10.
Tumors spleen 13.
Conclusion 14.
List of references 16.
Introduction
Selezenka (Lien, Splen) is an unpaired parenchymal body of the abdominal cavity; Performs immune, filtration and hematopoietual functions, takes part in the metabolism, in particular iron, proteins, etc. The spleen does not belong to the number of vital organs, but in connection with the functions listed, it plays a significant role in the body. Therefore, hematologists are most often faced with diseases of the spleen. If a few decades ago a spleen in a variety of situations, for example, during injuries or diseases, were removed, in fact, without thinking, today they use all the possibilities to save it.
The "unfinished" authority is attacked by tremendous importance, for it is known that it has the function of immunity, the protective properties of the body. Almost 50% of people whose spleen was removed as a child, do not live up to 50 years, because the immune system sharply decreases. In such patients, a high tendency to pneumonia, severe inflammatory and incognitage processes, which proceed violently and often with the development of sepsis - blood infection, as the protective function of the body changes. In recent decades, many studies and developments are aimed at maximizing the spleen as possible in cases where it is necessary to operate it.
Anatomy and histology of the spleen
The spleen is located in the abdominal cavity in the field of left hypochondrium at the level of the IX-XI ribs. The mass of C. is in adults 150-200 g, the length is 80-150 mm, the width is 60-90 mm, the thickness is 40-60 mm. The outer, the diaphragmal, the surface of the spleen is convex and smooth, internal - flat, has a furrow through which in S. includes arteries and nerves, veins and lymphatic vessels (the gate of the spleen) come out. C. Covered with a serous shell, under which there is a fibrous shell (capsule), more dense in the gate zone. From the fibrous shell, connecting to each other, radially directed trabecules, most of which contains intracracucular vessels, nerve fibers and muscle cells. The connective setting of S. C. is a musculoskeletal system that provides significant changes in the volume C. and the execution of a deposit function.
Blood supply S. carries out the largest branch of the ventricular barrel - the spleen artery (a. Leinalis), which passes more often along the top edge of the pancreas to the gate of the spleen (Fig.), Where it is divided into 2-3 branches. In accordance with the number of internal branches of the first order in C. allocate segments (zones). The branches of intraganic arteries pass inside the trabecul, then inside the lymphatic follicles (central artery). From lymphatic follicles, they exit in the form of brush arteriols equipped with so-called sleeves, consisting of reticular cells and fibers. Part of the arterial capillaries flows into sinuses (closed blood circulation), the other part is directly in the pulp (open blood circulation).
The spleen is distinguished white (from 6 to 20% of the mass) and red (from 70 to 80%) pulp. A white pulp consists of a lymphoid fabric located around the arteries: the periamaally most cells are T-lymphocytes, in the edge (marginal) area of \u200b\u200blymphatic follicles - in lymphocytes. With ripening in lymphatic follicles, light jet centers (reproduction centers) are formed containing reticular cells, lymphoblasts and macrophages. With age, a significant part of the lymphatic follicles is gradually atrophied.
The red pulp consists of a reticular island, arterioles, capillaries, a sinus type of veins and free cells (erythrocytes, platelets, lymphocytes, plasma cells), as well as nervous plexuses. The message of sinuses with a pulp through the cracks available in their wall in compression C. is interrupted, the plasma is partially filtered off, blood cells remain in sinus. Sinuses (their diameter from 12 to 40 μm, depending on the blood flow), are the first link of the spleen venous system.
Normal and pathological physiology.
The spleen is involved in cellular and humoral immunite, control over the circulating uniform elements of blood, as well as in blood formation, etc.
The most important feature of the spleen is immune. It lies in the seizure and processing of macrophages of harmful substances, blood purification from various alien agents (bacteria, viruses). Endotoxins are destroyed in the spleen, insoluble components of cell detread for burns, injuries and other tissue damage. The spleen is actively involved in the immune response - its cells recognize alien antigens for a given organism and synthesize specific antibodies.
The filtration (sequestration) function is carried out in the form of control over the circulating blood cells. First of all, this refers to red blood cells, both aging and defective. In the spleen, removal from red blood cells of granular inclusions (Taurus Zhli, the Taurus of the Heinz, the granules of iron) without the destruction of the cells themselves. Splenectomy and Atrophy of S. lead to an increase in the content of these cells in the blood. The increase in the number of siderocytes (cells containing iron granules) after splenectomy, and these changes are persistent, which indicates the specificity of this spleen function.
Spilenial macrophages reuterine iron from destroyed erythrocytes, turning it into transferin, i.e. Splezenka takes part in the exchange of iron.
It is believed that leukocytes in physiological conditions die in the spleen, lungs and liver; Platelets in a healthy person also destroy mainly in the spleen and liver. Probably, the spleen takes some more participation in thrombocytopoese, because After splenectomy, thrombocytosis occurs about damage to the spleen.
The spleen is not only destroyed, but also the shaped blood elements are accumulated - red blood cells, leukocytes, platelets. In particular, it contains from 30 to 50% and more circulating platelets, which, if necessary, can be thrown into the peripheral channel. In pathological conditions, their deposit is sometimes so great, which can lead to thrombocytopenia.
With a violation of blood outflow, for example, with portal hypertension, the spleen increases and can accommodate a large amount of blood. Reducing, the spleen is able to throw off the blood deposited in it in the vascular bed. In this case, its volume decreases, and the number of erythrocytes in the blood increases. However, the spleen norm contains no more than 20-40 ml of blood.
The spleen participates in the exchange of proteins and synthesizes albumin, globin (protein component of hemoglobin). The participation of the spleen in the formation of immunoglobulins is important, which is provided by numerous cells producing immunoglobulins, probably all classes.
The spleen takes an active part in blood formation, especially in the fetus. In an adult, it produces lymphocytes and monocytes. The spleen is the main organ of the extramedullary hematopoede in violation of the normal blood formation processes in the bone marrow, for example, with osteomyelofrosis, chronic blood loss, the osteoblastic form of cancer, sepsis, miliar tuberculosis, etc. There are indirect data confirming the participation of S. in the regulation of bone marrowing.
The great role of S. plays in hemolysis processes. It can delay and collapse a large number of modified erythrocytes, especially in some congenital (in particular, microspherocyte) and acquired hemolytic (including autoimmune nature) anemia. A large number of erythrocytes is delayed in C. With a stagnant, polycythemia. It is also established that the mechanical and osmotic resistance of leukocytes during passing through C. decreases.
C. Dysfunction is observed in some pathological conditions (severe anemia, some infectious diseases, etc.), as well as in hypersplenization - chronic increase in C. and decrease in blood cells of two or less often, one or three hematopopyic sprouts. It is assumed to be increased destruction in the spleen of the corresponding blood cells. Hyperplanism is primarily the pathology of the Red Pulp C. and is due to the hyperplasia of macrophage elements. After removal of C. With hypeplanism, the composition of the blood is usually normalized or significantly improved.
With hereditary and acquired violations of lipid exchange in the spleen, the accumulation of a large number of lipids is noted, which leads to splenomegaly.
The reduced function C. (hypipensism) is observed in atrophy S. in old age, during starvation, hypovitaminosis. It is accompanied by the appearance in the erythrocytes Taurus Zholly and target erythrocytes, siderocytosis.
Spleen man
Spleen (Lien, Splen) - non-fine, elongated form peripheral organ of lymphoid blood formation and immune protection, is deep in the back of the left hypochondrium. The length of the spleen is 10-12 cm, the width is 8-9 cm, the thickness is 4-5 cm, the mass of 150-200 g. The spleen is projected on the chest between 9 and 11, the long axis is located oscope and in most cases corresponds to the direction 10 of the ribs .
The main functions of the spleen:
1. Anatomy of the spleen
The spleen is distinguished by a diaphragmal and visceral surface. With its diaphragm surface, the spleen is adjacent to the lower surface of the diaphragm, visceral - to the bottom of the stomach, the left kidney, the left adrenal gland and in the colon. On the visceral surface of the spleen is a deepening - the gate of the liver, through which the spleen artery, nerves, veins and lymphatic vessels pass. The spleen from all sides is covered with peritoneum, which forms communication. Two bundles are divergent from the gate of the spleen: the gastrointestinal and diaphragm-spleen, which goes in the lumbar part of the diaphragm. In addition, the diaphragm to the left bending of the colon is undergoing a diaphragm-hazel bunch, which supports the front root of the spleen.
2. Histology of the spleen
The spleen is covered outside the connective tissue capsule, from which trabecules are deployed, forming a peculiar mesh frame. Capsule and Trabeculas form a supporting device of the spleen. They consist of dense fibrous connective tissue, in which elastic fibers prevail, allowing the spleen to change its dimensions and withstand a significant increase in volume. Capsule and Trabecules contain bundles of smooth myocytes, the reduction of which contributes to the pushing of deposited blood into the bloodstream. In the intervals between the trabecuchu, the model of the spleen is located, which is represented by a reticular tissue, and parenchyma cells are located in its loops. Parenchima includes two departments with different functions:
- white pulp
- red pulp
From so, the spleen refers to the parenchymal human bodies.
2.1. White pulp
The white pulp of the spleen is represented by a lymphoid fabric, lymph nodes (follicles) and lymphatic perigrian sheath.
Lymphatic follicles are in-dependent zones, which are formed by spherical accumulations of lymphocytes, plasmocytes, macrophages, dendritic and inter-cell cells. They are surrounded by a capsule that is formed by the reticuratelyalially cells. In the lymphatic follicles, white pulp spleen distinguish the following zones:
The lymphatic periaryal vagina is an elongated form of cluster of lymphocytes, which in the form of couplings covers the artery of white pulp spleen and continues to continue into the lymphatic follicle. In the central part of the vagina there are in lymphocytes and plasmacites, on the periphery - small T-lymphocytes.
2.2. Red pulp
It occupies the space between the white pulp and connecting trabecula. It consists of uniform blood elements that are accommodated among the reticular stroma. The red pulp includes:
3. The blood supply to the spleen
It is ensured by the spleen artery - the branch of the ventricular trunk. The initial artery department is placed behind the upper edge of the pancreas, and at the level of the tail of the gland artery comes out from under it and is divided into 2-3 branches, which are sent to the gate of the spleen. In the course, the spleen artery gives branches to the pancreas, and the short arteries of the stomach and the left gastrointestinal artery are departed at the gate of the spleen. The spleen vein has a diameter, twice as much as the items of the same name, and is often below the artery. Behind the head of the pancreas of the spleen vein, merging with the upper mesenteric vein, forms the main trunk of the petrite vein.
4. Lymphotok Selezenka
Regional lymph nodes of the first order are located in the gastrointestinal bundle at the gate of the spleen, as well as the tail of the pancreas. Next, the lymph is subject to the pidlslunkosalozomisosis nodes, and then into lymph nodes located around the root of the abdominal trunk.
5. Innervation of the spleen
The spleen innervates the branches of the spiley plexus, located around the spleen artery. In the formation of this plexus, abdominal, left diaphragmal and left adrenal nerve plexuses are involved.
Lymphatic nodes - the formation of a beanoid form, located in the course of lymphatic vessels, in which the antigen-dependent development of V- and T-lymphocytes in effector cells is carried out. The total mass of lymph nodes is 1% of body weight. By location, somatic, visceral and mixed lymph nodes differ. Their size is 5-10 mm.
Functions:
- ROOM - antigen-dependent differentiation of T- and B-lymphocytes.
- Barrier-protective: a) nonspecific protection - by phagocytosis of antigens by macrophages (coastal cells); b) Specific protection - by developing immune reactions.
- Drainage and deposit of lymph.
Development.
Limph nodes appear at the end of the 2nd and early 3rd month of embryogenesis in the form of clusters of mesenchym in the course of lymphatic vessels. By the end of the 4th month, the lymphocytes are made in the resulting from mesenchyma and lymphoid follicles are formed.
At the same time, the sines of lymphatic nodes are formed, a division into a cortical and brainstant. The full formation is completed in the 3-year-old age of the child. Follicle reactive centers appear in the immunization of the body. At the old age, the number of nodes decreases, the phagocytic activity of macrophages falls into them.
Structure.
Outside the lymphatic node is covered with a connecting sensor capsule.
With the convex side of the node through the capsule, bringing lymphatic vessels, and with the opposite - concave, called gate, exhibit enduring lymphososides, veins and include artery and nerves.
The connective tissue layers, which, together with the reticular tissue, form stroma are deployed from the capsule. The organ parenchyma is the cells of the lymphoid series. There are cortical and brainstasses (Fig. 12-3).
Cork substance Located under the capsule, formed by lymphatic follicles (nodules) having a spherical shape with a diameter of 0.5-1 mm. Lymphatic follicles are formed by clusters of B-lymphocytes, located at various stages of antigen-dependent differentiation, a small amount of macrophages and their type - dendritic cells. The latter fixes on their surface of antigens, keep the memory of these antigens and transmit information about them by developing in lymphocytes. Lymphoid follicles are a dynamic structure.
At the height of the immune response, the lymphatic nodules reach the maximum value. In the center of the follicle, staining lighter, there is a germinative (jet) center. The latter is reproduced under the influence of antigens of B-lymphoblasts, which, as the middle and small lymphocytes, are arranged in the peripheral, darker-colored follicle zone. An increase in the folliculum jet centers indicates an antigenic stimulation of the body. Endotheliocytes of sinuses are adjacent to the outer part of the follicles. Among them, a significant part is fixed macrophages ("coastal" cells).
Parakottic region Located on the border between the cortical and brainstant (T-zone). It contains mainly T-lymphocytes. The micro-generation for them is a type of macrophages that have lost the ability to phagocytosis - interdigrative cells. The latter produce glycoproteins that play the role of humoral lymphocytogenesis factors. They regulate the proliferation of T-lymphocytes and their differentiation into effector cells.
Brainstuff. The latter occupies a central position in the node, formed by cerebral (meal) hill, coming from the follicles to the gate of the node. A strare pulp forms a reticular tissue, between the cells of which the accumulations of the cortical substances of B-lymphocytes migrating from lymphoid follicles are located, plasmacites and macrophages. Outside of cerebral heavyness, like follicles, endotheliocytes of sinuses. Due to the presence of in-lymphocytes in the lymphatic follicles and brain jets, these formations are called in zones, and the paractic area is the T-zone.
In the cortical and cerebral substance between the connective tissue of the capsule and follicles and the sinuses are located between the brain hill. They are divided into edges (between capsules and follicles), angular, brain (between brain chas) and gate (at the gate). According to sines in the direction from the periphery of the node, Limph flows, enriched with lymphocytes and cleansing, as a result of the phagocytic activity of coastal cells from antigens. Paragocycable antigens can cause an immune response: proliferation of lymphocytes, converting in-lymphocytes in plasmocytes, and T-lymphocytes in effectors (T-killers) and memory cells.
Vascularization. Arteries enter the gate of the node. From them, hemokapillari penetrates from the connective tissue layers to the nodules, the paractic zone and the brainstorms. From the capillaries, running back, the venous system of the node is coming. Endothelium veins higher, there are pores.
Innervation. The afferent innervation of the lymphatic assembly is provided by pseudounipolar neurons of the corresponding spinal ganglia and neurons of the type of dogel type. Efferent innervation includes a sympathetic and parasympathetic link. There are minor intramural ganglia. Nerves are included in the lymphatic node along the blood vessels, forming a thick network in their Adventice. From this network, sprigs are departed by connecting interlayers in the brain and cortical substance.
Regeneration. Physiological regeneration of lymph nodes occurs constantly. Post-traumatic regeneration occurs when preserving bringing and reduced lymphosophosudes and lies in the proliferation of reticular tissue and lymphocytes.
Age changes. The final development of the structure of lymphatic nodes occurs in early childhood. Lymph nodes of newborns are rich in lymphocytes. Follicles with reproduction centers are rare. In the 1st year, reproduction centers appear, the number of in-lymphocytes, plasma cells increases. Up to 4-6 years continues the formation of brain seasures. By 12 years, the differentiation of lymph nodes ends. During aging, lymphatic follicles disappear with reproduction centers, the connecting stomach thickens. Some nodes are atrophy and replaced with a fatty tissue.
Hemolymphatic nodes NODI LYMPHATICI HAEMALIS)
This is a special type of lymph nodes, in the sines of which blood circulates, and not lymph and perform the functions of lymphoid and myeloid blood formation. In humans, hemolymphatic nodes are rarely found and arranged in an oilcommunica fiber, around the abdominal aorta, less often in the rear mediastone.
Development Hemolymphatic assemblies are very similar to the development of ordinary lymph nodes.
Structure. The magnitude of hemolymphatic nodes are less than lymphatic, characterized by less developed brainagery and follicles. With age, hemolymphatic nodes are subjected to involutions. The cortical and brainstant is replaced by a fatty cloth or in the latter sprouts a loose fiber junction tissue.
Spleen (Splen, Lien)
The spleen is an unpaired organ of the extended form located in the left hypochondrium of the abdominal cavity. Its mass is 100-150 gr.
Functions:
- Bleeding - reproduction and antigen-dependent differentiation of T- and B-lymphocytes.
- Deposit - blood depot, iron, platelets (up to 1/3 of their total).
- Endocrine - synthesis of erythropoietin - a stimulating erythropoese, tftsin - peptide, which stimulates the activity of phagocytes, splinn - analogue of thymopoietin, stimulating blastransformation and differentiation of T-lymphocytes.
- Elimination and destruction of old erythrocytes and platelets.
- The embryonic period is a universal blood formation body.
Development. The spleen laying occurs on the 5th week of embryogenesis from the mesenchyma of the dorsal mesentery. Initially, all uniform elements are extravasively formed in the spleen, and after 5 months of embryogenesis, lymphopoeodez prevails in it.
Structure. Splezenka - a parenchymal organ. Outside is surrounded by a connective tissue capsule covered with mesothelium. The capsule is represented by a dense fibrous connective tissue, between the collagen fibers of which are located in a small amount of smooth muscle cells. Trabecules are deployed from the capsule, which together form a refractory apparatus. The space between the trabeculas is filled with a reticular tissue forming a stroma organ.
The spleen is an unpaired organ located in the abdominal cavity at a large curvature of the stomach, in the ruminants - on the Rubam. Shape varies from flat elongated to a rounded; In animals of different species, the shape and sizes may be different. The color of the spleen - from intense red-brown to blue-purple - due to the large number of blood contained in it.
Fig. 212. Network almonds:
BUT - dogs, B. - Sheep (by Ellenbergeru and Trutman); but - Snacks almonds; b. - epithelium; in - reticular tissue; g - lymphatic follicles; d. - loose connective tissue; e. - glands; j. - Muscular fibers.
Splezenka - multifunctional organ. In most animals, this is an important organ of lymphocyt formation and immunity, which is under the influence of antigens present in the blood, the cells are the formation of cells or producing humoral antibodies or involved in cellular immunity reactions. In some animals (rodents), the spleen is a universal blood formation organ, where cells of lymphoid, erythroid and granulocytic sprouts are formed. The spleen is a powerful macrophage. With the participation of numerous macrophages, it is destroyed by blood cells and especially erythrocytes ("Erythrocyte Cemetery"), the decay products of the latter (iron, proteins) are re-used in the body.
Fig. 213. Cat spleen (by Ellenbergeru and Truttanu):
a - capsule; b. - Trabez; in - Trabecular artery; g. - trabecular vein; d. - Bright center of the lymphatic follicle; e. - Central Artery; j. - red pulp; z. - Vascular vagina.
Selezenka - Blood deposit authority. Especially pronounced by the deposit function of the spleen at the horse and ruminants.
A spleen is developing from the clusters of quickly breeding cells of mesenchyma in the region of the dorsal part of the mesentery. In the initial period of development, the layout occurs from the mesenchyma of the fibrous frame, the vascular channel and the reticular stroma. The latter is settled by stem cells and macrophages. Initially, this is the organ of myeloid blood formation. Then there is an intensive ventilation from the central lymphoid organs of lymphocytes, which first are uniformly around the central arteries (T-zone). B-zones are formed later, which is associated with the concentration of macrophages and lymphocytes on the side of the T-zones. Simultaneously with the development of lymph nodules, the formation of red spleen pulp is observed. In the early posthambrium period, the increase in the number and volume of the nodules, the development and expansion of the reproduction centers in them is noted.
Microscopic structure of the spleen. The main structural functional elements of the spleen is a supporting apparatus represented by a capsule and a tracculus system, and the rest of the intersectoral part - the pulp, built mainly from the reticular tissue. There are white and red pulp (Fig.213).
The spleen is covered with a serous shell, tightly struggling with a connective tissue capsule. The crossloves are depressed - trabecules, forming a kind of network-shaped frame. The most massive trabeculas at the gate of the spleen, they are located large blood vessels - trabecular arteries and veins. The latter belong to the veins of an indefinite type and on the preparations quite clearly differ in the structure from the wall of the arteries.
Capsule and Trabecules consist of dense fibrous connective and smooth muscle tissue. A significant amount of muscle tissue is developing and contained in the spleen of the deposit type (horse, ruminants, pigs, predatory). Reducing the smooth muscle tissue contributes to the pushing of deposited blood into the bloodstream. In the connecting tissue of the capsule and trabeculs predominate elastic fibers, allowing
the spleen change its size and withstand a significant increase in its volume.
White pulp (Pulpa Lienis Alba) macroscopically and on unpainted preparations represents a combination of light gray rounded or oval formations (nodules), illegally dispersed throughout the spleen. The number of nodules in different animal species is different. There are many cattle in the spleen of cattle and they are distinctly excluded from the red pulp. Less nodules in the spleen of a horse and pig.
With light microscopy, each lymphatic nodule is an formation consisting of a complex of lymphoid tissue cells located in the adventitization of the artery and numerous hemokapillars derived from it. Artery nodule is called Central. However, it is more often located eccentric. In the developed lymphatic assembly, several structural and functional zones are distinguished: a periaryal, a bright center with a mantle zone and a marginal zone. The periraial zone is a peculiar coupling consisting of small lymphocytes, closely adjacent to each other and inter-cell cells. The lymphocytes of this zone belong to the recycling Foundation of T-cells. Here they penetrate the hemocapillars, and after antigenic stimulation can migrate in the sines of red pulp. Interdigrative cells are special process macrophages that absorb antigen and stimulating blastransformspe, proliferation and conversion of T-lymphocytes in effector cells.
The bright center of the node in structure and functional purpose corresponds to the follicles of the lymphatic node and is a thymus-dependent area. Here there are lymphoblasts, many of which are in the stage of mitosis, dendritic cells that fix the antigen and preserving it for a long time, as well as free macrophages containing absorbed lymphocyte decay products in the form of painted calves. The structure of the Light Center reflects the functional state of the lymph node and can change significantly in infections and intoxication. The center is surrounded by a dense lymphocytic rim - the mantle zone.
Around the entire nodule is a marginal zone. which contains T- and B-lymphocytes and macrophages. It is believed that in a functionality, this zone is one of the sections of the cooperative interaction of different types of cells in the immune response. The in-lymphocytes located in this zone as a result of this interaction and stimulated by the appropriate antigen are proliferated and differentiated into antibody-forming plasma cells accumulated in the heavy pulp hoods. The form of the spleen nodule is supported using the reticular fiber network - in the thymus-dependent section, they are located radially, and in the T-zone - along the long axis of the central artery.
Red pulp (Pulpa Lienis Rubra). The extensive part (up to 70% of the mass) of the spleen, located between the lymph nodes and Trabez. Due to the content of a significant amount of red blood cells in it, there has a red color of spleen preparations. It consists of reticular tissue with free cellular elements in it: blood cells, plasma cells and macrophages. Numerous arterioles, capillaries and peculiar venous sinuses (Sinus Venosus) are found in the Red Pulp (Sinus Venosus), in their cavities, the most diverse cell elements are deposited. The red pulp is rich in sinus on the border with a marginal zone of lymphatic nodules. The number of venous sinuses in the spleen of animals of different species is not the same. There are many rabbits, guinea pigs, dogs, smaller cattle, large and small cattle. Plots of red pulp, located between sinus, are called spleen. or pulp heavy, the composition of which many lymphocytes and the development of mature plasma cells occurs. Macrophages of pulp heavys are carried out by phagocytosis of damaged red blood cells and are involved in the exchange of iron in the body.
Circulation. The complexity of the structure and multifunctionality of the spleen may be understood only due to the peculiarities of its blood circulation.
Arterial blood is directed to the spleen on the spleen artery. Which through the gate enters the body. From the artery, branches running inside the major trabeculs and called trabecular arteries. In their wall there are all shells peculiar to the arteries of muscle type: intima, media and adventization. The latter growls with the trabecular connective tissue. From the trabecular artery, the artery of small caliber is departed, which come into the red pulp and are called pulp arteries. Around the pulp arteries, elongated lymphatic vagina are formed, as they devote from the trabecuch, they increase and take a spherical shape (lymphatic nodule). Inside these lymphatic formations from the artery, many capillaries depart, and the artery itself gets the name of the central one. However, the central (axial) location is available only in the lymphatic vagina, and in the nodule - eccentric. Upon comes from the nod., this artery decays to a row of twigs - brush arterioles. Around the final sections of the brush arterioles are oval accumulations of elongated reticular cells (ellipsoids, or sleeves). In the cytoplasm of endothelium of ellipsoid arterioles, microfilaments were found with which the ability of ellipsoids is reduced - the function of peculiar sphincters. The arterioles are further branched to the capillaries. Part of them flows into venous sinuses of red pulp (the theory of closed blood circulation). In accordance with the theory of open blood circulation, arterial blood
from the capillaries goes into the reticular tissue of pulp, and it seeps over the wall into the cavity of the sinuses. Venous sinuses occupy a significant part of the red pulp and can have different diameter and shape depending on their blood flow. Thin walls of venous sinuses are lined with intermittent endothelium located on a basal plate. On the surface of the sinus wall in the form of rings there are reticular fibers. At the end of the sinus, at the place of passing it to Vienna, there is another sphincter.
Depending on the reduced PQ relaxes of arterial and venous sphincters, sinuses can be in various functional states. When reducing venous sphincters, blood fills the sines, stretches their wall, while the blood plasma goes through it into the reticular tissue of pulp, and in the cavity of the sinuses is accumulated by uniform elements of blood. In the venous sinuses of the spleen can delay up to 1/3 of the total number of red blood cells. With both sphincters open, the contents of sinuses enters the bloodstream. It is often happening with a sharp increase in oxygen need when the sympathetic nervous system is arising and the relaxation of sphincters. This also contributes to the reduction of smooth muscles capsules and trabecul spleen.
The outflow of venous blood from the pulp occurs through the vein system. The wall of the trabecular veins consists only of endothelium, closely adjacent to trabeculic tissue, that is, these veins do not have their own muscle shell. This structure of trabecular veins facilitates the pushing of blood from their cavity to the spleen vein, which emerges through the gate of the spleen and flowing into a gate vein.
Spleen ( splen., lien.) - the peripheral and largest organ of the immune system, located in the course of blood vessels. The functions of the spleen include:
- - participation in the formation of humoral and cellular immunity, delayed antigens circulating in the blood;
- - elimination from blood flow and, then, destruction of old and damaged red blood cells and platelets, - "Selezenka - Erythrocyte Cemetery";
- - blood deposition and platelet accumulation (up to 1/3 of the total number of them in the body);
- - in the embryonic period - the hematopoietic function.
The spleen occurs antigen-dependent proliferation and differentiation of T- and B-lymphocytes and the formation of antibodies, as well as the production of substances that depress erythropoes in.
Development. A person has a spleen in the 5th week of the embryonic period of development in the thickness of the mesenchyma of the dozen mesentery. At the beginning of the development of the spleen is a dense accumulation of mesenchymal cells, permeated by primary blood vessels. In the future, some cells are differentiated into a reticular tissue, which is settled with stem cells. At the 7-8th week of development in the spleen appear macrophages. At the 12th week of development of the spleen for the first time, in-lymphocytes with immunoglobulin receptors appear. The processes of myelopopower in a person's spleen reaches maximum development at the 5th month of the intrauterine period, after which they decrease their activity and at the time of birth cessing at all. The main function of myelopoose by this time is performed by a red bone marrow. The processes of lymphocytopoede in the spleen by the time of birth, on the contrary, are strengthened.
On the 3rd month of embryonic development in the vascular bed of the spleen appear wide venous sines, separating it to the islands. Initially, the islands of the blood-forming cells are located evenly around the artery (T-zone), and on the 5th month the concentration of lymphocytes and macrophages on the side of it (in-zone) begins. By this time, the population of in lymphocytes, detected by immunological methods, is about 3 times higher than the T-lymphocyte population. Simultaneously with the development of the nodules, the formation of red pulp, which becomes a morphologically distinguishable in the 6th month of intrauterine development.
Structure
The spleen is covered with a connective tissue capsule and peritoneum (mesothelium). The capsule consists of containing fibroblasts and numerous collagen and elastic fibers. Between the fibers, there is a small amount of smooth muscle cells.
Inside the organ from the capsule deplochant - trabez spleenwhich in the deep parts of the body anatomize among themselves. The capsule and trabecules in the spleen of a person occupy about 5-7% of the total volume of the organ and make up its supporting and contractor. In the trabecs of the spleen of a person relatively slightly smooth. Elastic fibers in trabecules are more numerous than in the capsule.
Stroma The organ is represented by reticular cells and reticular fibers containing collagen III and IV types.
Parenchyma (or pulp) The spleen includes two departments with different functions: a white pulp ( pulpa Lienis Alba.) and a red pulp ( pulpa Lienis Rubra.).
The structure of the spleen and the ratio between white and red pulp may vary depending on the functional state of the organ.
White pulp spleen
The white pulp of the spleen is represented by a lymphoid fabric located in the adventitia of the arteries in the form of spherical clusters, or nodules, and lymphatic periaterial vagina. In general, they constitute about 1/5 organs.
Lymphatic nodules spleen (follicles, or Malpigayev Taurus; lymphonoduli Splenici.) 0.3-0.5mm in diameter are clusters of T- and B-lymphocytes, plasmocytes and macrophages in reticular tissue loops (dendritic cells) surrounded by a capsule from flattened reticular cells. Through the lymphatic nodule passes, usually eccentric, central artery (a. Centralis), from which radial capillaries depart.
Lymphatic nodules spleen (like lymph nodes) - are B-dependent Zone white pulp spleen. In the lymph nodules there are 4 unclearly distinguished areas: a periaryal, reproduction center, mantle and edge, or marginal, zone.
The periraterial zone occupies a small section of the nodal near the central artery and is a continuation of the perigrian vagina (i.e., it is formed mainly from T-lymphocytes that come here through the hemokapillars that depart from the artery of the lymphatic nodule). Submicroscopic processes of interdigrative cells are pulled out by a significant distance between their surrounding lymphocytes and are tightly in contact with them. It is believed that these cells adsorb antigens coming here with blood flow, and transmit information about the state of microenvironment to T-lymphocytes, stimulating them blast transformation and proliferation. For 2-3 days, activated T-lymphocytes remain in this zone and multiply. In the future, they migrate from the periraidic zone in the sinuses of the edge zone through the ge-mocapillary. The same way fall into the spleen and in-lymphocytes. The reason for the settlement of T-and B-lymphocytes of "its" zones is not enough. In functionality, the periraterial zone is an analogue of a parakoctic thymus-dependent zone of lymph nodes.
The reproduction center, or the germinative center of the nodule, consists of reticular cells and proliferating B-lymphoblasts that are differentiated antibody-forming plasma cells. In addition, it is often possible to detect clusters of macrophages with phagocyte lymphocytes or their fragments in the form of chromophilic cells and dendritic cells. In these cases, the central part of the nodder looks light (so-called "Jet Center").
The periphery of the lymphatic nodule - the mantle zone - surrounds the periaryal zone and the center of the reproduction, consists mainly of densely located small in-lymphocytes and a small amount of T-lymphocytes, and also contains plasmocytes and macrophages. Seasoned tightly to each other, cells form a crown, stratified with circularly directed thick reticular fibers.
Periiarical lymphatic vagina (Palv, vagina Periaristerialis Lymphatica.) They represent their elongated pulp artery of the cluster of lymphoid fabric. Periiarical lymphatic vagina are T-dependent Searen zone.
The edge, or marginal, the zone of spleen nodules is a transition area between white and a red pulp of about 100 microns. It seems to surround lymphatic nodules and periraidic lymphatic vagina, consists of T- and B-lymphocytes and single macrophages, surrounded by edge, or marginal, sinusoid vessels with slick-like pores in the wall.
Blood antigens are delayed in the marginal zone and red pulp. Next, they are transferred to the macrophages to the surface of antigen-representing cells (dendritic and interfigitating) white pulp. Lymphocytes from blood flow sediated mainly in the periaryal zone (T-lymphocytes) and in lymphoid nodules (in lymphocytes). With a primary immune response, the producing cells of the cells appear first in ellipsoid clutches, and then in the red pulp. With a secondary immune response, breeding centers are formed, where clones of in-lymphocytes and memory cells are formed. Differentiation of in-lymphocytes in plasmacites is completed in the red pulp. Regardless of the type of antigen and the method of its introduction, the accumulation of lymphocytes in the spleen occurs not so much due to their proliferation, as due to the inflow of the cells already stimulated by an antigen.
Red pulp spleen
The red spleen pulp includes venous sinuses and pulp tires.
Pulp tall. A portion of the red pulp, located between sinus, is called splenic, or pulp, hoods (Chordaee splenicae). These are uniform elements of blood, macrophages, plasma cells lying in reticular connective tissue loops. Here, by analogy with the brainagery of lymphatic nodes, they finish their differentiation and secrete plasmocyte antibodies, the predecessors of which are moved here from white pulp. In pulp, there are clusters of v- and T-lymphocytes, which can form new nodules of white pulp. Monocytes are delayed in the red pulp, which are differentiated into macrophages.
The spleen is considered the "red blood cell cemetery" due to the fact that it has the ability to reduce the osmotic stability of old or damaged red blood cells. Such erythrocytes are not capable of entering venous sines and are destroyed and absorbed by the macrophages of the red pulp.
As a result of the cleavage of hemoglobin absorbed by the macrophages of erythrocytes, bilirubin and containing iron transferin are produced and released into blood flow. Bilirubin is transferred to the liver, where the bile will enter. Transferrin from blood flow is captured by bone marrow macrophages, which are equipped with iron newly developing red blood cells.
Blood deposited in the spleen and platelets accumulate. Old platelets are also destroyed here.
Sinuses of red pulplocated between splenic hoods, are part of the sophisticated spleen vascular system. These are wide thin-walled vessels of the irregular shape, are lined with endothelial cells of an unusual spindle-shaped form with narrow slits between them, through which the shaped elements migrate into the lumen of the surrounding seewers. The base membrane is intermittent, it is complemented by reticular fibers and the process of reticular cells.
Vascularization. A spleen artery is included in the spleen gate, which branches the trabecular artery. The outer shell of the arteries loose is connected to the troubled fabric. The average shell is clearly noticeable on any section of the trabecular artery due to muscle beams, which makes it the walls of the spiral. Pulp arteries depart from trabecular arteries. In the outer shell of these arteries, many spiral elastic fibers, which provide longitudinal stretching and reduction of vessels. Not far from Trabez in the Adventition of Pulp arteries, perigatical lymphatic vagina and lymph nodes appear. Artery gets the name of the central one.
The central artery, passing through the nodule, gives several hemokapillars and, coming out of the node, branches in the form of a brush for several brush arteriols (ARTERIOLAE PENICILLARIS). The distal end of this arteriole continues in an ellipsoid (gillard) arteriolaeelipsoideae (ARTERIOLAELIPSOIDEAE), equipped with a clutch (or "sleeve") from reticular cells and fibers. This is a kind of sphincter on the arteriole. In humans, these sleeves are very weak. In the endothelium of the sleeve or ellipsoid arterioles, contractile philots were detected. Next follow short hemokapillary. Most of the red pulp capillaries flows into venous sinuses (this is so-called. Closed blood circulation), but some can directly open into the red pulp reticular tissue (this is the so-called. Open blood circulation). Closed blood circulation is the path of rapid circulation and oxygenation of tissues. Open blood circulation is slower, providing contact of blood shaped blood elements with macrophages.
Sinuses are the beginning of the venous spleen system. Their diameter ranges from 12 to 40 microns, depending on the blood flow. When expanding, the totality of all sines occupies most of the spleen. Endotheliocytes of sinuses are located on an intermittent basal membrane. On the surface of the sinus wall in the form of rings there are reticular fibers. Sinuses do not have pericitis. In the entrance to the sinuses and at the place of their transition to the veins there are similarities of muscle sphincters. With open arterial and venous sphincters, the blood is fluent in sinus in veins. Reducing the venous sphincter leads to the accumulation of blood in sine. The blood plasma penetrates through the sinus wall, which contributes to the concentration of cell elements in it. In case of closure of venous and arterial sphincters, blood deposit in the spleen. When tensile sinuses between endothelial cells, slots are formed through which blood can pass into the reticular strom. The relaxation of arterial and venous sphincters, as well as the reduction in smooth muscle cells of the capsule and the trabecul leads to emptying the sines and blood output to the venous direction.
The outflow of venous blood from the pulp spleen is performed through the veins system. Trabecular veins are deprived of their own muscular layer; The middle shell in them is very weak. The outer sheath of the veins is tightly fragmented with a trabecula junction. Such a structure of the veins determine their gaping and facilitates blood release while reducing smooth muscle cells of the spleen. Anastomoses are found between the arteries and veins in the spleen capsule, as well as between the pulp arteries.
Innervation. In the spleen there are sensitive nerve fibers (dendrites of neurons of the cerebrospinal nodes) and postganglionic sympathetic nerve fibers from solar plexus nodes. Myeline and miserable (adrenergic) nerve fibers are found in capsule, trabecules and plexuses around trabecular vessels and arteries of white pulp, as well as in sinus spleen. The nerve endings in the form of free end branches are located in the connective tissue, on smooth muscle cells of trabecula and vessels, in the reticular stroma of the spleen.
Age-related changes. At the old age in the spleen, the white and red pulp atrophy occurs, as a result of which its trabecular apparatus is extended more clearly. The number of lymph nodules in the spleen and the dimensions of their centers are gradually reduced. The reticular fibers of white and red pulp are stubble and become more winding. In sense of senile age, knocked thickening of the fibers are observed. The number of macrophages and lymphocytes in the pulp decreases, and the number of granular leukocytes and fat cells increases. Children and senior people in the spleen are found gigantic multi-core cells - megakaryocytes. The amount of iron-containing pigment, reflecting the process of death of the erythrocytes, with age in the pulp increases, but it is mainly extracellular.
Regeneration. The physiological update of lymphoid and stromal cells occurs within the limits of independent stem differons. Experimental studies on animals showed the possibility of restoring the spleen after removal of 80-90% of its volume (reparative regeneration). However, the complete restoration of the shape and size of the organ, as a rule, is not observed.
Some terms of practical medicine:
- splenomegaly (splenomegalia; Spleno- + Greek. megas. large; syn. megality) - a resistant increase in the spleen;
- spleen wandering (lien Mobilis.) - spleen, excessively displaced due to the weakness of its ligament apparatus; more often anomaly of development;
- searen glaze - spleen with a sharply thickened fibrous capsule, as if covered with icing; morphological sign of chronic polyporosite;
- porphyrian spleen (lien Porphyricus.) - an increased dense spleen with a multitude of gray nodules on the section; morphological sign of generalized lymphoganululetsis;
- spotzen spotted (lien Maculatus.) - an enlarged dery spleen, having a spotted view due to the uneven filling blood; observed in acute blood loss and shock;
- splecean Sagovaya - increased dense spleen, having yellowish gray areas, resembling grains of Sago; observed in focal sediments of amyloid, mainly in lymphoid follicles;
- spleceneka in Selezenka (lien in Liene.) - anomaly of development, in which the second spleen, having its capsule, is found in the center of the spleen;
- Pappenheim Cell (A.Pappenheim, 1870--1917, it. Doctor; Sin. Pappenheim splenocyte) - monocyte formed in the spleen reticular tissue;
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