RESUMO
The arrangement of collagen and elastic fibers of the membranous part of the interventricular septum (PMS) was studied in hearts from adult humans. Connective bundles formed a network of fairly independent tendons arranged in two layers. The tendinous bundles consisted essentially of type I collagen fibers while type III fibers were visible as a thin network with transversely and longitudinally oriented meshes around the muscle bundles. Cranial and caudal to the PMS were narrow and irregular bands of collagen fibers that apparently represented zones of low resistance to the high blood pressures acting from the left to the right heart chambers. The predominance of fiber bundles arranged in an approximately transverse direction with regard to the arterial cone axis suggests a resistance to enlargement resulting from high aortic blood pressure. Elastic fibers were observed in the transitional zone between the cardiac muscle and the PMS. They were continuous with elaunin fibers and these with oxytalan fibers closely intermingled with the narrow network of type I collagen fibers of the PMS. The successive transformation of elastic fibers, which were very numerous in the muscle-tendon transition, into elaunin and these into oxytalan fibers toward the central portions of the PMS suggests a functional sequence characterized by a high elasticity and consequent mobility of the transition region itself and by a progressive increase of resistance in this portion.
Assuntos
Coração/anatomia & histologia , Adulto , Idoso , Cadáver , Colágeno/ultraestrutura , Tecido Elástico/anatomia & histologia , Tecido Elástico/ultraestrutura , Septos Cardíacos/anatomia & histologia , Septos Cardíacos/ultraestrutura , Ventrículos do Coração/anatomia & histologia , Humanos , Microscopia Eletrônica de Varredura , Microscopia de Polarização , Pessoa de Meia-IdadeRESUMO
We determined the effect of dietary sodium intake (0.15 and 8% NaCl) on the cardiac neuron size of normotensive 3-week old Wistar rats. An increase in dietary sodium for 48 weeks induced an increase in neuronal size. The number of large neurons (larger than 500 microns 2) increased significantly (chi-square test) in rats ingesting 8% NaCl in their food. The rats presented hypertension (128 +/- 9 vs 134 +/- 16 mmHg; difference not significant, Student t-test) and a statistically significant increase in cardiac muscle mass (1.6 +/- 0.1 vs 2.0 +/- 0.2 mg/g of rat). We conclude that food sodium can significantly increase cardiac nerve cell size and this trophic response occurs concomitantly with an increase of cardiac muscle mass.
Assuntos
Cardiomegalia/fisiopatologia , Hipertensão/induzido quimicamente , Neurônios/efeitos dos fármacos , Sódio na Dieta/farmacologia , Animais , Cardiomegalia/etiologia , Distribuição de Qui-Quadrado , Hipertensão/etiologia , Miocárdio/patologia , Neurônios/fisiologia , Ratos , Ratos WistarRESUMO
We determined the effect of dietary sodium intake (0.15 and 8 per cent NACl) on the cardiac neuron size of normotensive 3-week old Wistar rats. An increase in dietary sodium for 48 weeks induced an increase in neuronal size. The number of large neurons (larger than 500 muM2) increased significantly (chi-square test) in rats ingesting 8 per cent NaCl in their food. The rats presented hypertension (128 ñ 9 vs 134 ñ 16 mmHg; difference not significant, Student t-test) and a statistically significant increase in cardiac muscle mass (1.6 ñ 0.1 vs 2.0 ñ 0.2 mg/g of rat). We conclude that food sodium can significantly increase cardiac nerve cell size and this trophic response occurs concomitantly with an increase of cardiac muscle mass.
Assuntos
Animais , Ratos , Hipertensão/induzido quimicamente , Cardiomegalia/fisiopatologia , Neurônios , Sódio na Dieta/farmacologia , Hipertensão/etiologia , Cardiomegalia/etiologia , Miocárdio/patologia , Neurônios/fisiologia , Ratos WistarRESUMO
The arrangement of the smooth muscle and elastic and collagen fibers of the minor papilla of the human duodenum was studied on 53 duodenopancreatic specimens obtained from adults of both sexes. Methods included stereological analyses of gross anatomical specimens and thick and thin microscopic sections. The muscular and elastic fibers of the minor papilla have a unidirectional arrangement by which the contraction of its smooth muscular fibers causes opening of its orifice allowing the flow of the pancreatic juice into the duodenum. It is not a typical anatomical sphincter.
Assuntos
Duodeno/anatomia & histologia , Ductos Pancreáticos/anatomia & histologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Colágeno , Tecido Elástico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Músculo Liso/anatomia & histologia , Suco Pancreático/fisiologiaRESUMO
The morpho-functional relationships between the hepato-duodenal ligament and the superior part of the duodenum are analysed. Twenty-four specimens were removed during necropsies of adults and prepared according to various mesoscopic, microscopic, and ultramicroscopical methods, i.e., whole-mounts, membrane preparations, thick and thin histological sections, and polarized light, scanning, and transmission electron microscopy were employed. The hepato-duodenal ligament is formed by longitudinally elongated, type I collagen fiber bundles which are interlinked by more delicate bundles of type III collagen fibers. Longitudinally disposed elastic fibers are the principal component of the elastic fiber system of the ligament. These are in continuity with the elaunin and oxytalan fibers which are intermingled with the muscle cells of the vessels and duodenal wall, and fat cells of the ligament. Part of the muscle bundles of the external, longitudinal, muscle layer of the duodenum is anchored in the adventitial and subserosal collagen and elastic fiber framework of the organ while part inserts directly into the fibrous framework of the ligament. The fibrous system of the ligament is continuous with that of the subserosa and adventitia of the duodenum.
Assuntos
Duodeno/anatomia & histologia , Ligamentos/anatomia & histologia , Fígado/anatomia & histologia , Cadáver , Duodeno/fisiologia , Humanos , Ligamentos/ultraestrutura , Fígado/fisiologia , Microscopia EletrônicaRESUMO
Cast of the mucosal and submucosal veins of the esophago-gastric junction were studied in five necropsy specimens by scanning electron microscopy to analyse some of the characteristics of their shape and surface. Two types of veins were described: 1) veins with circumscript, fusiform and/or ampullar bulges and relatively smooth surfaces; 2) veins with numerous, small bulges and blister-shaped micro-dilatations. The role of these features is considered in the formation of esophageal varices.
Assuntos
Junção Esofagogástrica/irrigação sanguínea , Adulto , Feminino , Humanos , Masculino , Microscopia Eletrônica de Varredura , Veias/ultraestruturaRESUMO
1. The myenteric plexus of the small intestine of five C57BL/6J male 5-month-old mice was investigated in whole-mount preparations of the muscularis externa by Giemsa staining and by the acetylcholinesterase (AChE) histochemical technique. 2. The neuronal density was 20212 +/- 3038/cm2 (mean +/- SEM) in the duodenum, 21948 +/- 1488/cm2 in the jejunum, and 25048 +/- 2356/cm2 in the ileum. The difference in neuronal density between duodenum and ileum was statistically significant (P < 0.05). The total serosal surface area of the small intestine was about 30.80 +/- 2.90 cm2, and the total number of neurons was estimated at about 690,000. 3. The neuronal cell and nucleus profile areas ranged, respectively, from 23 to 325 microns 2 and from 6 to 95 microns 2 in the small intestine of the mice studied. There were no significant differences in any of the 3 regions in terms of average neuronal cell or nucleus profile areas. 4. For the histochemical demonstration of AChE, the "direct coloring" copper ferrocyanide method was used. AChE-positive nerve fibers were distributed in the myenteric plexus which was formed by a primary meshwork of relatively large nerve bundles and a secondary meshwork of finer nerve bundles. Most of the neurons of the plexus displayed AChE activity in the cytoplasm though the neurons presented different reaction intensities.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Acetilcolinesterase/análise , Intestino Delgado/inervação , Plexo Mientérico/anatomia & histologia , Animais , Contagem de Células , Duodeno/inervação , Histocitoquímica , Íleo/inervação , Jejuno/inervação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plexo Mientérico/enzimologia , Neurônios/químicaRESUMO
The arrangement of muscle, collagen and elastic fibers was studied in the retro- and suprahepatic (subdiaphragmatic) portions of the inferior vena cava, the hepatic veins and their main affluents. Distinctive features of the longitudinal and transverse muscle bundles are described. In these portions of the vena cava, both bundle systems are clearly separate and any continuity was observed only at the entrances of the hepatic veins. A musculo-venulolymphatic complex was noted in spurs formed by the vascular junctions. The hepatic veins and their main affluents exhibit an elliptical contour in transverse section, which apparently results from cranial and caudal thickenings of the longitudinal muscle layer. Many of these bundles are in continuity with those of the transverse muscle layer. Terminal elastic tendons were rarely observed in connection with muscle fibers of the inferior vena cava and are not present in the hepatic veins and their main affluents. In terms of form and function, the relatively thin muscular layer has a dilating action on the hepatic venous system because of the external fixed insertion point of the muscle bundles. Such an arrangement and a "polar" disposition of the muscle bundles in the hepatic venous system may assists in "suction" of the blood toward the heart. A sphincteric control of the ostia by means of crossed muscular loops supported by venulo-lymphatic micropads is a possibility.
Assuntos
Veias Hepáticas/anatomia & histologia , Veia Cava Inferior/anatomia & histologia , Colágeno/ultraestrutura , Humanos , Circulação Hepática/fisiologia , Músculo Liso Vascular/citologiaRESUMO
In works already published, it was made clear that many researches were interested in the absorption phenomena, permeability and structure of the visceral mesothelial tissue. Attention was concentrated on the mesentery and observations were made using the application of lanthanum nitrate and osmium-amine. The penetration of lanthanum nitrate is impeded by the basement membrane situated between the connective and mesothelial tissues. The heavy salt moves through and not between the mesothelial cells by passive diffusion. No reaction was observed in general with osmium-amine, with the exception of a few cases. In those instances, the osmium-amine reacted not only in the outer surface of the mesentery, but also penetrated with no visible reaction all the way to the connective tissue where it was detected in the elastic layer. In this paper, the colloidal iron was employed using different techniques, and depositions were detected in the surface of the mesentery, in the mesothelial cells and also in the connective tissue. A final conclusion that the permeability of different layers of tissues is of great variety and has a definite capacity for selectivity is suggested.
Assuntos
Ferro/metabolismo , Mesentério/metabolismo , Absorção , Animais , Coloides , Mesentério/ultraestrutura , Microscopia Eletrônica , Permeabilidade , RatosRESUMO
The connective tissue associated with the myenteric plexus of the human oesophagus was studied by light and electron microscopy. Collagen fibres were identified by picrosirius staining with polarization microscopy and from their fine structural morphology. A capsule of connective tissue invests the ganglia while septa of connective tissue separate groups of ganglion neurons, surrounding each individual ganglion neuron and each nerve bundle. Collagen fibrils surround the ganglia, each ganglion neuron and each nerve bundle. The fibrils are disposed in various orientations forming networks. Elastic, elaunin and oxytalan fibres were identified by their staining characteristics and fine structural morphology. The bulk of the ganglion sheath consists of coarse elastic fibres and elaunin fibres. Elaunin and oxytalan fibres form the intraganglionic network. Oxytalan, elaunin and elastic fibres appear to be located in areas related to different stresses and deformation to which the ganglia of the myenteric plexus are exposed during the contraction of the esophageal wall. The ganglia of the myenteric plexus of the human oesophagus show structural organisation of the connective tissue component similar to that seen in sympathetic and parasympathetic ganglia.