Phrynops geoffroanus é o quelônio onívoro com mais ampla distribuição geográfica na América do Sul. Este trabalho descreve a histologia e histoquímica do tubo digestório desta espécie, relacionando as características dos órgãos com seu hábito alimentar. O esôfago, estômago e intestino de quatro espécimes foram fixados em formol 10% e incluídos em parafina por técnica histológica de rotina. Depois, cortes de 5 µm de espessura foram corados com hematoxilina-eosina (HE), ácido periódico de Schiff (PAS) e alcian blue (AB) pH 0.4 e 2.5. O tubo é formado pelas camadas mucosa, submucosa, muscular e adventícia ou serosa. A mucosa do esôfago e do estômago é revestida pelo epitélio simples cilíndrico com células mucossecretoras, onde estão inseridas glândulas intraepiteliais na porção do esôfago e fossetas gástricas desembocando em glândulas no estômago. O estômago divide-se em anterior, médio e posterior, de acordo com a profundidade das fossetas e a concentração de glândulas gástricas. O intestino é revestido pelo epitélio simples cilíndrico com borda estriada e células caliciformes e divide-se em anterior e posterior, de acordo com o padrão de dobramentos da mucosa e o número de células caliciformes. Reatividade ao PAS e AB é observada em todo o tubo. Fibras musculares lisas estão presentes na camada mucosa de todos os segmentos. A camada muscular é formada por duas subcamadas de músculo liso, exceto na porção posterior do estômago. Este estudo ajudará no entendimento da fisiologia digestiva da espécie investigada e fornecerá dados para análises comparativas com outros quelônios.

Phrynops geoffroanus is the omnivorous chelonian with widest geographical distribution in South America. This work describes the histology and histochemistry of the digestive tube of this species, to relate the characteristics of these organs to the species' eating habit. The esophagus, stomach and intestine of four specimens were fixed in 10% formal and embedded in paraffin by routine histological techniques. Afterwards, 5-µm sections were stained with hematoxylin-eosin (HE), periodic acid-Schiff (PAS) and alcian blue (AB) pH 0.4 and 2.5. The tube is formed by the mucosa, submucosa, muscular and adventitia or serosa layers. The mucosa layer of the esophagus and stomach is lined with a simple cylindrical epithelium with mucus-secreting cells, where are intraepithelial glands inserted in the portion of the esophagus and gastric fossettes emptying into glands in the stomach. The stomach is divided into an anterior, middle and posterior region, according to the depth of the fossettes and the concentration of gastric glands. The intestine is lined by a simple cylindrical epithelium with striated boundaries and goblet cells and is divided into an anterior and posterior regions, according to the pattern of folds of the mucosa layer and the number of goblet cells. Reactivity to PAS and AB is observed in the entire tube. Smooth muscle fibers are present in mucosa layer of all the segments. The muscular layer is formed by two sub-layers of smooth muscle, except for the posterior stomach. This study will help understanding of the digestive physiology of P. geoffroanus and provide data for comparative analyzes with other turtles.

The ontogenesis of the gastroesophageal mucosa involves morphological alterations related to its structure and the function of each segment. The present study describes the histogenesis of the mucus-secreting epithelium and glands of the esophagus, gizzard, and proventriculus of the chicken (Gallus gallus), and identifies alterations in the secretion pattern of glycosaminoglycans (GAG's). We analyzed 38 chicken embryos, processed the material collected following the histological routine, and then stained it with hematoxylin-eosin for the analysis of tissue structure and with Gomori's trichrome for the identification of conjunctive tissue and collagen fibers. We used the PAS histochemical technique for the analysis of neutral GAG's and the AB pH 2.5 histochemical technique for the analysis of acid GAG's. The embryos at late stage of development had the esophagus wall composed of four layers: mucosa, submucosa, muscularis, and serosa, whereas the proventriculus and the gizzard were composed of three layers: mucosa, muscularis, and serosa. In all three segments, we identified the superficial epithelium as mucus-secreting; in the esophagus this epithelium was mucus-secreting only at the initial development stages. The proventricular glands began to form at the initial development stages, whereas the tubular glands began to form in the gizzard just after the 15th day. The differences in the production of GAG's in these regions of the digestive tract are related to development stages, functions, and physiological requirements of each segment, and to the gradual adjustment of the body to the post-hatching life.

La morfogénesis de la mucosa gastroesofágica implica alteraciones morfológicas relacionadas con su estructura y la función de cada segmento. El presente estudio describe la histogénesis del epitelio secretor mucinoso y de las glándulas del esófago, molleja y proventrículo del pollo (G. gallus), ademas de identificar los cambios em el patrón de secreción de glicocosaminoglicanos (GAG's). Se utilizaron treinta y ocho embriones de pollo. El material recogido fue procesado de acuerdo a la rutina histológica y posteriormente las secciones se tiñieron con hematoxilina-eosina para su análisis histológico, con tricrómico de Gomori para identificar el tejido conectivo y las fibras de colágeno y con PAS y AB pH 2,5 para el análisis GAG's neutro y ácido. En una etapa avanzada de desarrollo de los embriones, se pudo obervar en la pared del esófago cuatro capas: mucosa, submucosa, muscular y serosa, mientras que el proventrículo y molleja se muestra constituida por tres capas: mucosa, muscular y serosa. En los tres segmentos de la superficie, el epitelio se identificó como mucinoso y en el esófago sólo en la etapa inicial de desarrollo. Las glándulas del proventrículo se empiezan a formar en las primeras etapas de desarrollo, mientras que en las glándulas tubulares de la molleja comienzan su sólo después del día 15. Las diferencias en la producción de GAG's en estas regiones del tracto digestivo están relacionadas con las etapas de desarrollo, las funciones y necesidades fisiológicas de cada segmento del cuerpo y se adapta gradualmente a la vida después de la eclosión.

Objetivou-se avaliar as características morfométricas de ovários recuperados de bovinos em diferentes estádios reprodutivos. Os ovários utilizados (N=200) foram obtidos em matadouro e transportados para o laboratório, onde foram realizadas as mensurações do tamanho do órgão, dos folículos e corpos lúteos. Os pares de ovários foram classificados em função do estádio reprodutivo, da fase do ciclo estral ou do período de gestação dos animais dos quais foram recuperados. Observou-se que o tamanho do ovário diferiu (P<0,001) entre os animais pré-púberes e pós-púberes. Não se observou diferença (P>0,05) no tamanho do órgão entre os animais apresentando AOLC ou gestantes, porém nestes o corpo lúteo foi maior e o diâmetro do maior folículo menor (P<0,05). Os parâmetros em estudo também foram afetados pela fase do ciclo estral (P<0,05) e pelo período da gestação (P<0,05). Nos animais com AOLC, observou-se uma correlação significativa entre o tamanho do ovário e o do corpo lúteo (R=0,69; P<0,01). Conclui-se que as características morfológicas do ovário variam em função do estádio reprodutivo, podendo ser utilizadas como parâmetro na avaliação clinica e funcional do órgão.

The aim of this study was to evaluate morphometric characteristics of bovine ovaries recovered on different reproductive stages. The ovaries used (N=200) were recovered at slaughterhouses and sent to the laboratory, were the size of the ovary, of follicles and of corpus luteum were measured. The pairs of ovaries were classified according to the reproductive stage, and to the estrous cycle or pregnancy stages of the animals from which they were recovered. There was a difference (P<0,001) on ovarian size between pre and postpuberal animals. There was no difference (P>0,05) on organ size between animals presenting estrous cycles or pregnancy, but pregnant cows presented larger corpora lutea and smaller diameter of the largest follicle (P<0,05). Evaluated parameters were affected by estrous cycle and pregnancy stages (P<0,05). There was a significant correlation between ovary and corpus luteum sizes in the animals presenting estrous cycles (R=0.69; P<0,001). In conclusion, ovarian morphologic characteristics changes according to the reproductive stages, could be used as parameters for clinic and functional evaluations of the organ.

The observations made about the stomach of Trichogenes longipinnis (Britski & Ortega, 1983) showed a rounded organ which has in its dorsal side an accessory structure - a cul de sac - that comunicates with it. The distal part of this dorsal accessory presents characteristic of an organ that exercise respiratory functions: reduction in the thickness of the mucosa and arrangement of an intrincate continuous capilar net in close contact with the superficial cells of the epithelium. In this portion there are no glands in the lamina propria. The epithelium shows a superficial squamous cels; they are very slim, and sometimes, with the capillary endothelium form a single barrier between the organ lumen and the blood. Polyhedric cells are also present in this epithelium; they are located under the squamous cells, sheltered between capillaries and basal cells.

Trichogenes longipinnis (Britski & Ortega, 1983) is a leather fish restricted to the rivers on the shore in the southeast of Brazil. In this work, the oesophagous structure is being showed. The oesophagous appears itself short, dorsally inclinated toward pericardium and ventrally covered by liver lobe. By electron microscopy we can observe a mucosa layer formed by stratified squamous epithelium and lamina propria with stratum compactum. The epithelium is composed by three types of cells: superficial squamous cells; mucous cells, similar to the globet cells and polyhedric cells. The stratification of this epithelium provides a complete basal layer of proliferation polyhedric cells. The cells in the intermediate region of the epithelium are also polyhedric. These cells are just bellow the superficial squamous cells and packed among mucous cells.