Ultrastructure of mesenteric lymphatic postcapillaries of the small intestine of the human fetus

Lymphatic vessels of the small intestine mesentery have been investigated in 36 human fetuses 3-6-month-old. Lymphatic postcapillaries are the predominant link in the lymphomicrocirculatory bed studied. They differ from the capillaries only by presence of valves. Intersegmentary valves and velves at the places where the lymphatic capillaries get into the postcapillaries are described; they are situated along the whole length of the postcapillary. Both types of the valves can be uni- and besinusoid, and according to the number of endotheliocytes, covering the sinuses, uni- and multicellular. Cells of fibroblastic line and developing collagenous fibers are inevitable structural components and situate in their base. Ultrastructural peculiarities of the lymphatic postcapillary wall are described. Structural mechanisms responsible for dilatation and narrowing of the vascular lumen (formation of the pulse wave) are discussed. The data obtained support the conception successively elaborated by V. V. Kuprianov on the lymphatic postcapillary as an inevitable link of the lymphomicrocirculatory bed.     

Development of the lymphatic bed of the human esophageal wall]

The lymphatic capillaries are firstly determined in fetuses at the age of 3-4 months in the oesophagus submucous lamina. In fetuses of 5-6 months of age transition of the lymphatic capillaries from the submucous lamina into the mucous membrane proper is noted. In fetuses of 6 months of age perivascular lymphatic capillaries and vessels appear. They form peculiar paths around arterioles, venules, arterial branches and venous tributaries. The lymphatic bed of the oesophageal wall is rather well developed in mature fetuses and newborns. In adult and old persons a partial reduction of the lymphatic bed in the oesophageal wall is observed.     

The relationship between the lymphatic vessels of the nerves of the human lower extremity and the perineural spaces]

The lymphatic vessels and perineural spaces of superficial and profound nerves of the extremity were studied on the material of 50 lower extremities of corpses of humans by the method of intratissue and direct injection. Initial lymphatic capillaries and extraorganic lymphatic vessels and their paravasal plexuses were found. It is concluded that closed lymphatic capillaries having no immediate connection with the perineural space are the roots of the lymphatic bed in the nerve.     

Structural changes in the small intestine wall and its lymphatic bed after gastrectomy

Morphologically and histochemically structural changes of the small intestine wall and its lymphatic bed have been studied in 104 dogs after the stomach resection. After the operation an increase in the diameter of the lymphatic capillaries and vessels takes place. Lateral dilatations and protrusions in the capillary walls appear, new anastomoses in all the membranes are formed, they are mostly manifested in the mucous membrane. Histopathological rearrangement in the small intestine wall is demonstrated as edema of the mucous membrane, as plethora of the vessels, as lymphoid infiltration and as changes of the villi forms.     

Surgical anatomy of the anterior abdominal wall in normal viscera, dolichoviscerosis and visceroptosis

There are three types in position of the abdominal internal organs: visceronorm, dolichoviscerosis and visceroptosis. The anterior abdominal wall also has its own anatomical peculiarities at every type of the internal organs position. Anatomical differences of its structure at visceronorm and dolichoviscerosis in comparison with visceroptosis are characterized as following: the area of aponeurotic formations of the anterior abdominal wall at dolichoviscerosis and visceroptosis increases and that of the muscular-decreases. Umbilical and inguinal rings are essentially dilated in comparison with those at visceronorm. It means that at dolichoviscerosis and visceroptosis there are anatomical prerequisites for development of external hernias in the anterior abdominal wall. A considerable mobility of the intestinal tract loops at dolichoviscerosis and visceroptosis results in certain disturbances of its function and their outlet into hernial sacs.     

Structure of lymphatic vessels in the rat thyroid gland

The lymphatic bed of the thyroid gland has been studied in 24 intact rats. Three techniques facilitating to reveal lymphatic vessels in the organ have been used: preparation of semithin sections, injection of the blood bed with methyl methacrylate with a successive chemical extraction of the preparations, injection of the blood bed with liquid solution of methyl methacrylate with a consecutive study of the preparations in the scanning electron microscope. Methods of electron histochemistry (revealing horseradish peroxidase) and kryofractography have been applied. Construction of the thyroid lymphatic bed, structure of the wall are described, fibroblastic membrane (F-membrane) is revealed and the signs are presented, that allow to differentiate F-membrane from endothelium of the lymphatic capillaries. The pathways of lymph outflow in the rat thyroid gland consist of the following links: interstitial space in the interlobular spaces of the gland, into them the tissue liquor (lymph) is filtered ; plates of the F-membrane regulating direction of excessive albumin-containing liquor in the lymphatic capillaries, surrounding groups of 5-11 follicles, embracing the microlobule of the gland and situating in the interlobular spaces, deferent lymphatic vessels.     

Age and variability in the inguinal lymph nodes of adult humans]

Lymphatic nodes on the anterior surface of the femur, in the region of the femoral triangle were studied in 56 corpses of humans of either sex from 31 to 82 years of age, dead of accidental causes or of diseases not related to lymphatic nodes. The investigation was carried on by the method of interstitial and direct injection of the Gerota's mass to some regions of foot skin, external genitalia and the skin of the anterior wall of the abdomen. It has been established that the size of inguinal lymphatic nodes (both superficial and profound) in humans of either sex, are in direct dependence on the age of the person. The amount of inguinal lymphatic nodes in young people prevails over that in old people. The external diameter of the afferent and efferent vessels in elderly humans is greater than in young ones. The amount of afferent lymphatic vessels to inguinal lymphatic nodes in most cases prevails over the amount of efferent ones, independent of age and sex. The external diameter of the former is greater than that of the latter.     

Intraorganic lymphatic bed of the cattle heart

Lymphomicrocirculatory networks of endocardium, myocardium and epicardium, as well as lymphatic vessels of four orders represent the intraorganic lymphatic bed of the cattle heart. In the endocardium there is a lymphatic network with close loops and a small amount of blindly beginning capillaries. The capillary lymphatic bed of the endocardial trabeculae carneae is much more dense than that in the other part of the endocardial surface. The spatial lymphatic network of the myocardium is joined with the lymphomicrocirculatory networks of the endocardium and epicardium by means of a large amount of connections. The epicardial lymphatic bed is formed by blindly beginning lymphatic capillaries, which situate in close and nonclose loops of the lymphatic network. In the epicardium there is only one lymphatic network. The size of the loops and the diameter of the lymphatic capillaries is directly proportional to the age of the animals.     

Ultrastructure of the lymphatic capillaries of the diaphragm and their interrelationship with peritoneal mesothelium

In 28 mature rats, ultrastructure of the diaphragmal lymphatic capillaries and mesothelial tegmen was studied. Interrelation of their cellular elements and possible ways of metabolic absorbtion from the abdomen were clarified. The diaphragmal lymphatic capillaries were demonstrated to situate under mesothelial cells and they are separated by a thin layer of longitudial collagenic fibers. As cross section of the lymphatic capillary demonstrates, the capillary wall consists of 3--6 endothelial cells with a set of organelles, among which are: mitochondria, Golgi's complex, some pinocytotic vesicles.     

Morphofunctional changes in the hemo- and lymphomicrocirculatory bed of the uterus and its regional lymph nodes in venous congestion during pregnancy

Interrelations of the blood and lymphatic systems of the uterus have been examined in rats at pregnancy complicated with the ++phlebo-occlusive syndrome. Blood stream impediment in the caudal vena cava results in increasing diameter of the arterioles, capillaries and venules of the endo- and myometrium. Certain disturbances of blood circulation in the uterus at the ++phlebo-cclusive syndrome in the pregnancy animals, as a rule, reflect in the uterine lymph outflow; this is demonstrated as dilatation and deformity of the lymphatic vessels and capillaries, appearance of protrusions of the lymphatic vessels wall. There is a definite co-ordination in the reaction to the caudal vena cava occlusion in the intra-, ++extra-organic uterine lymphatic bed and in its regional lymph nodes, manifested as the following morphological signs: decreasing relative volume, that the lymphoid tissue occupies and increasing relative volume of the cortical and medullary intermediate sinuses.     

Sex and type peculiarities of the topography of the anterior abdominal wall in adult persons of various ages]

In men and in "masculine" shape of the abdomen as compared with women and "feminine" shape of the abdomen the following features of the topography of the anterior-lateral abdominal wall were revealed: a narrower white line, wider straight muscles of the abdomen in their medial and upper parts, less square surface of the lateral muscle-free portions. The inguinal region of men and the "musculine" type of the abdomen are characterized by great dimensions of the superficial and profound rings, weaker aponeurosis of the external oblique abdominal muscle in formation of the anterior wall of the inguinal canal. In elderly and senile age there occur dilatation of the white line, the increase of the amount of chinks and apertures in it as well as of the length of aponeuroses. The superficial inguinal ring expands.     

Microscopic and ultrastructural study of the lymphatic system in the human parotid gland

The localization and fine structure of the lymphatic system vessels are examined in the human parotid gland. A network of lymphatic capillaries extends in the intralobular connective septa around the striated ducts. These lymphatics converge in collectors frequently bordering the excretory ducts. On the contrary, no lymphatics are present next to the intercalated ducts and adhenomers. Ultrastructurally, the lymphatic capillaries are characterized by a very thin endothelial wall and by slightly complicated intercellular adhesions. Open junctions are also present. The presence of numerous lymphatic capillaries bordering the striated ducts and their blood microvasculature is discussed in relation to the functional activities of the striated ducts in the modification of the saliva.     

Structural interrelations of the air-blood barrier and terminal sections of the lymphatic link in the pulmonary microcirculatory bed in chronic hypervolemia

The interalveolar septa of the human lungs are known to have no lymphatic capillaries. The topography of the pulmonary lymphatic system origin under conditions of chronic hypervolemia is still not investigated. Lungs of 24 corpses of persons, died from non-pulmonary pathology (control) and lungs of 34 corpses of persons, died from congenital and acquired heart disease accompanied with pre- and postcapillary forms of the pulmonary circulation hypertension, have been investigated. Decreased efficiency of the microcirculation, increased permeability of the blood capillary walls against the background of hypoxia result in an elevated production of lymph. Intensified collagen formation in the blood vessel walls and in the interalveolar septa is the prerequisite for reorganization of the pulmonary lymphatic bed. Lymphatic capillaries are found to grow into some sclerotic interalveolar septa and into deep structures of the blood capillary walls. This demonstrates a high plasticity of the lymphatic link terminal parts of the microcirculatory bed in pathologically changed lungs.     

Scanning electron microscope study of the liver microcirculation

During the experimental investigation performed in dogs and rats, by means of scanning electron microscopy of corrosive anatomical preparations, the spatial organization of all parts of the hepatic vascular bed (arterial, venous and lymphatic) has been studied, specific features of their components construction have been described. Within the limits of one hepatic lobule the number of vessels included in the portal vein system exceeds that of the arterial ones, originating from the proper hepatic artery system. In every part of the vascular bed the gradient of the form, orientation and pronouncement of the nuclei-containing zones in endotheliocytes and myocytes has been established. Various appliances participating in the blood and lymph stream regulation in different parts of the vascular bed have been revealed. As initial elements of the lymph bed, closed digital or loop-like capillaries should be regarded, they localize in the organ's connective tissue framework. Around the portal and hepatic veins and their branches, as well as around the biliary ducts, well developed plexuses of the lymphatic and blood capillaries and vessels localize, they are the main draining pathways of the organ. The degree of development and pronouncement of these plexuses depends on the lumen size in the formation they accompany.     

The intraorganic lymphatic bed of the mucous membrane of the tongue

The intraorganic lymphatic bed of the canine tongue mucous membrane is presented by the superficial and deep capillary networks and by the plexuses of the intraorganic lymphatic vessels. The capillaries of the superficial network in the thickness of the mucous membrane of the dorsal surface of the lingual tip, body and root form the lymphatic bed of the mechanical and gustatory papillas. The diameter of the capillaries in the both networks and in the intraorganic lymphatic vessels is greater in the mucous membrane of the ventral surface of the tip and of the lateral surfaces of the lingual body, and density of their arrangement is higher in the mucous membrane on the dorsal surface of the lingual tip, body and root. The capillaries of the superficial network in all areas of the lingual mucous membrane are thinner than those of the deep network, and the loops formed by the capillaries of the superficial network are less than the loops of the deep network.     

Structure and function of lymphatic postcapillaries (coordinating mechanism of the processes of interstitial transport and lymphatic resorption

Investigation performed on topography, structure and resorptive function of lymphatic microvessels in the serous membranes gives possibilities to work out a model on formation and transport of lymph. Lymphatic postcapillaries (LP) - thin-walled endothelial channels with valves make an important link of the lymphatic system. The LP structure is similar to that of capillaries. These microvessels are situated in the interstitial space area, that are characterized with their high content of plasma proteins and water. Interrelation in concentrations of protein in the LP lumen and in the tissue ensures the existence of the osmotic gradient pressure through the wall and contributes liquor resorption into the lumen of microvessels. Peritoneal lymphatic capillaries are situated in the areas of a higher hydrotation level of the interstitial space. They can control the rate of the liquor filtration from plasma into tissue and regulate the resorption level in the whole lymphatic network. The model provides a differentiated participation of the LP and capillaries in performing resorption of proteins and liquor from the interstitium. The resorption mechanisms are closely connected with processes of the lymph movement along the vessels.     

Various characteristics of the structure of the cardiac lymphatic bed and the morphofunctional basis of its insufficiency

Structural peculiarities of the cardiac lymphatic bed have been studied, as well as its adaptive and pathological changes under physical load, acute and recurrent coronary insufficiency under conditions of mechanical blockade of the lymph outflow from the organ, which have been modelled in dogs and rabbits. The cardiac lymphatic bed is injected with various staining masses and investigated stereoangioscopically in translucent preparations, in semithin slices and electron microscopically. The rearrangement of lymphatic capillaries and vessels revealed is of stereotypical character. The degree of manifestation and correlation of morphofunctional reactions, characterizing development of insufficiency of the cardiac lymphatic vessels is mainly determined by intensity and exposition of pathological effects, exercised on it, while etiologic factors are of less importance.     

Peritoneal fine structure of inguinal hernia: a scanning electron microscope study

Mesothelial cells of the normal human peritoneum of the anterior abdominal wall are covered with numerous surface microvilli. These cells become partially denuded inside the sacs of direct and indirect inguinal hernias and so lose the protective property the microvillar covering may impart on them. These mesothelial cells of hernial sacs also acquire an extensive surface coat of fibrin-like material, presumably due to the loss of that protective property, which may as a result subject them to adhesions. There is a considerable collagen build-up in the subserosal fibrous tissue of sacs of both direct and indirect inguinal hernias. Such a build-up is at variance with the accepted current surgical concept which suggests a defect in collagen synthesis, rather than a build-up, as the cause of direct hernia.     

Anatomic transformation of the lymphatic bed of the small intestine following immunization]

The experimental investigation of the lymphatic bed of the small intestine after immunization was performed in 15 rabbits. Ten rabbits were taken as control. The rabbits were immunized by administration of kidney antigen with the complete Freund adjuvant. The animals were killed on the 7-8th days after two cycles of immunization, three injections in each cycle. The interval between the injections was three days, between the cycles - one month. Polychrome injection of arteries and veins was made. The lymphatic bed was filled with Gerota's mass. The chylus sinuses, lymph capillaries and vessels of experimental animals were found to be dilated 2-6 times as compared with normal. There appear many blind processes on the walls of lymph capillaries and vessels. Intraorganic lymphatic pathways were more dilated as compared with extraorganic. The ileum was found to be more reactive in immunization than other two parts of the small intestine.     

Morphofunctional characteristics of the hemomicrocirculatory bed of the canine pericardium

The hemomicrocirculatory bed in the canine pericardium is presented by arterioles, precapillaries, capillaries, postcapillaries and venules situating in various connective tissue layers of the pericardium. Certain morphological peculiarities of the structure of the hemomicrocirculatory bed links are revealed in various parts of the pericardium. As demonstrate morphometry data, the diameter of all the vessels of the hemomicrocirculatory bed in various parts of the pericardium has no precise differences. There are some fluctuations in the number of the capillaries per 1 mm2 in various parts of the pericardium. Their number is comparatively greater in the area of the vascular porta (transitional fold), in the left lateral, in the ventral and dorsal parts of the pericardium. In these parts of the pericardium the density of the capillaries is increased, the network is especially dense in the area where the pericardial transitional fold passes into the epicardium. In the pericardial microcirculatory blood bed adaptive mechanisms (glomeruli, arteriolo-venular anastomoses, microsphincters) performing regulation of the organ's blood stream, are widely presented.