Concepções de alunos do ensino médio sobre o tema água: subsídios para o planejamento de atividades investigativas interdisciplinares

Meaningful learning occurs when new knowledge to be aggregated are grounded in other students already possess. In preparing didactic sequences for teaching concepts, one should take into account these concepts and knowledge to produce more effective and lasting learning, and build new concepts that will become subsumes for subsequent learning. This research was developed in a subproject linked to institutional Scholarship Program Initiation to Teaching (PIBID) of a Universidade Estadual Paulista. The proposal is based on the articulation of the Public School and the University, strengthening the initial training of undergraduates, and continued teacher network, improving the quality of education. The proposed work is based on interdisciplinary research and teaching by investigation. Undergraduates in Biology, Physics, Mathematics and Chemistry jointly propose interdisciplinary teaching activities and investigative applied to high school students of Public School partner. To survey the views of these students on the theme Water, they were asked to draw up an essay entitled "The importance of water", with the aim of organizing information for planning a teaching strategy that articulates the disciplines of training of undergraduates. In this paper we present a qualitative analysis of these essays, performed based on content analysis. The analysis allowed to identify existing concepts in students' cognitive structure and classify them into adequate and inadequate compared to scientifically accepted concepts. Several misconceptions were raised indicating the need to produce didactic sequences that in addition to working the concepts presented in the curriculum of disciplines take into consideration the possibility of more meaningful learning. This research produced the elucidation of existing concepts, indicating where deficiencies were larger. One major contribution was the realization that concepts that may be considered by teachers as simple and already acquired by the students often come so misguided in their explanations. From the results obtained, integrated activities have been planned and implemented, and more relevant to the needs of students aiming to recover and enrich the knowledge they possessed, encouraging the use of scientific concepts and their application to daily living situations.A aprendizagem significativa ocorre quando novos conhecimentos a serem agregados estão embasados em outros que os estudantes já possuam. Ao elaborar sequências didáticas para o ensino de conceitos, devem-se levar em consideração estas concepções e conhecimentos para produzir aprendizagens mais eficazes e duradouras, e construir novas concepções que se tornarão subsunções para aprendizagens subsequentes. Esta pesquisa foi desenvolvida em um subprojeto institucional vinculado ao Programa Institucional de Bolsas de Iniciação à Docência (PIBID) de uma Universidade Estadual Paulista. A proposta baseia-se na articulação da Escola Pública e Universidade, fortalecendo a formação inicial de licenciandos, e a continuada dos professores da rede, melhorando a qualidade de ensino. A proposta de trabalho fundamenta-se na interdisciplinaridade e no ensino por investigação. Os licenciandos em Biologia, Física, Matemática e Química propõem coletivamente atividades de ensino interdisciplinares e investigativas aplicadas aos estudantes do Ensino Médio da Escola Pública parceira. Para o levantamento das concepções desses estudantes sobre o tema Água solicitou-se que elaborassem uma redação intitulada “A importância da água”, com o objetivo de organizar subsídios para o planejamento de uma estratégia de ensino, que articulasse as disciplinas de formação dos licenciandos. Neste trabalho apresentamos a análise qualitativa destas redações, realizada com base na análise do conteúdo. As análises possibilitaram identificar os conceitos existentes na estrutura cognitiva dos estudantes, bem como classificá-los em adequados e inadequados em comparação aos conceitos cientificamente aceitos. Foram levantadas diversas concepções equivocadas indicando a necessidade de se produzir seqüências didáticas que, além de trabalhar os conceitos presentes no currículo das disciplinas, levassem em consideração a possibilidade de aprendizagens mais significativas. Essa pesquisa produziu a elucidação dos conceitos existentes, indicando onde as deficiências eram maiores. Uma das importantes contribuições foi à percepção de que conceitos que podem ser considerados pelos professores como simples e já adquiridos pelos estudantes, muitas vezes surgem de maneira equivocada em suas explicações. A partir dos resultados obtidos foram planejadas e aplicadas atividades integradas, relevantes e mais adequadas às necessidades dos estudantes visando resgatar e enriquecer os conhecimentos que eles possuíam, fomentando a utilização dos conceitos científicos, e sua aplicação às situações de vivência diária

Light microscopy and ultrastructure ight of the liver of Astyanax altiparanae Garutti and Britski, 2000 (Teleostei, Characidae) = Histologia e ultraestrutura do fígado de Astyanax altiparanae Garutti e Britski, 2000 (Teleostei, Characidae)

Livers of thirty specimens of Astyanax altiparanae obtained from a commercial fish farm were subjected to light and transmission electron microscopy, in order to describe the hepatic parenchyma and the intrahepatic exocrine pancreatic tissue. Anatomically, theliver showed only three hepatic lobes. Histological analysis demonstrated that the hepatocytes were spread out as anastomotic cords, arranged in two cellular layers and surrounded by sinusoids. The intrahepatic exocrine pancreatic tissue exhibited an acinararrangement and was diffused in the hepatic parenchyma. Ultrastructural analysis showed that the hepatocytes had a rounded nucleus and a rough endoplasmatic reticulum, with a parallel disposition to the nuclear membrane. The exocrine pancreatic cells showed secretion granules at the apical portion, and the rough endosplasmatic reticulum was concentrically distributed.<br><br>Fígados de 30 exemplares de Astyanax altiparanae, obtidos de pesqueiros, foram submetidos à microscopia de luz e à microscopia eletrônica de transmissão para descrição do parênquima hepático e do tecido pancreático exócrino intrahepático. Anatomicamente, o fígado apresenta somente três lobos hepáticos. A análise histológica demonstra que os hepatócitos se encontram arranjados na forma de cordões anastomosados, dispostos em duas camadas celulares, sendo que estes estão cercados por sinusóides. O tecido pancreático exócrino intra-hepático apresenta arranjo acinar difuso pelo parênquima hepático. A análise ultraestrutural demonstra que os hepatócitos possuem um núcleo arredondado e retículo endoplasmático rugoso, com disposição paralela à membrana nuclear. As células pancreáticas exócrinas apresentam grânulos de secreção na porção apical e retículo endoplasmático rugoso com distribuição concêntrica

altiparanae Garutti and Britski, 2000 (Teleostei, Characidae)

Light ight microscopy and ultrastructure of the liver of Astyanax styana

<b>Estudo morfológico do tecido hepático de <em>Leporinus macrocephalus</em></b> - DOI: 10.4025/actascibiolsci.v29i1.157 Morphological study of the hepatic tissue of <em>Leporinus macrocephalus</em>

O presente trabalho objetivou análise macroscópica e histológica do fígado de <em>Leporinus macrocephalus</em> para avaliar a estrutura do tecido hepático. Os peixes provenientes de um pesqueiro da região de Bauru, Estado de São Paulo, foram anestesiados, mortos, e os fígados foram retirados e encaminhados à rotina histológica, com inclusão em paraplast. A macroscopia mostrou um figado de estrutura homogênea, de coloração marron-avermelhada, localizado na região medial do corpo, caudalmente ao coração e posterior às brânquias, apresentando três lóbos de forma piramidal, sendo um central e dois laterais direito e esquerdo. A análise histológica revelou o tecido hepático constituído por cordões duplos de hepatócitos circundados por sinusóides, denominado de “muralha dupla”. Revelou, ainda, um sistema biliar disperso pelo parênquima hepático mostrando ductos com epitélio cúbico simples, circundado por fibras musculares e tecido conjuntivo. Células do tecido pancreático exócrino foram observadas, margeando vasos sangüíneos, organizando-se em ácinos apresentando grânulos de zimogênio. Além disso, existem centros melanomacrófagos distribuídos ao longo de todo parênquima, preferencialmente próximos aos vasos sanguíneos, formados por células que acumulam materiais como melanina e lipofucsina, podendo sua presença estar relacionada com o estado nutricional do peixe<br>The objective of this work was to analyze the liver of <em>Leporinus macrocephalus</em> at the macroscopic and histologic level by evaluating the characteristics of the hepatic tissue. The fishes from a fishery in Bauru, S.P., were collected and sacrificed by destroying the spinal cord; afterwards the collected hepatic tissue was fixed and followed by histological routine. Macroscopic analysis of <em>L. macrocephalus</em> liver showed an organ of homogeneous structure, with red-brown color, located in the medial region of the body, caudal to heart and after the gills. It showed 3 pyramidal lobes, one central and two lateral right and left. The histological analysis showed the hepatic tissue constituted by hepatocytes cords surrounded by sinusoids, named “muralium duplex”. It yet revealed the diffused, distribution bile system by hepatic parenchyma, showing ducts with simple cubic epithelium, surrounded by muscular fibres and connective tissue. Cells of the exocrine pancreatic tissue were observed surrounding blood vessels in acinar arrangement as zymogen granules. Furthermore, there are melanomacrophages centers distributed along the hepatic parenchyma, preferably next to the blood vessels, constituted by cells accumulating material, such as melanin and lipofucsin, whose presence may be related to the nutritional status of the fis

Morphology and Histochemistry of the Liver of Carnivorous Fish Hemisorubim platyrhynchos

The aim of this study was to characterize the normal structure of the liver of Hemisorubim platyrhynchos, a carnivorous freshwater catfish found in Neotropical region, using gross anatomy, histology and histochemistry. Anatomically, the liver presents C-shaped and only two lobes: smaller right and bigger left. The gallbladder is located in right lobe and shows elongated shaped. Histological analysis demonstrated that the hepatic parenchyma is made of two hepatocytes plates surrounded by sinusoids. The hepatocytes are polygonal-shaped cells, with spherical nucleus and a dark prominent nucleolus. The cytoplasm presents large amount of lipids and glycogen deposits PAS positives. There are no hepatic lobules or portal triads. Bile ducts are lined by columnar epithelial cells with apical mucosubstances PAS and AB positive. Furthermore, the liver presents melano-macrophages centers, distributed next to the blood vessels and bile ducts, constituted by cells accumulating pigments, whose presence may be related to the nutritional status of the fish. Moreover pancreatic tissue was observed in visceral portion of liver, formed by exocrine pancreatic tissue and islet organ, constituting an extrahepatic pancreas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

A histological study of the seminal vesicle of the armoured catfish Corydoras aeneus

Most species of Corydoras exhibited a reproductive behaviour called 'T-position', and exhibited an accessory gland in the male genital tract, called the seminal vesicle. It appeared that both the structure and the composition of the fluid varied considerably between the species investigated. Consequently, different opinions were proposed regarding the possible role of seminal vesicle on this particular reproductive behaviour. Male adults of Corydoras aeneus were collected, anaesthetized, and samples of seminal vesicle were fixed in Bouin's solution. The sections were stained with haematoxylin-eosin and periodic acid Schiff. The seminal vesicle showed a system of anastomosed secretory tubules, forming a vesicular collective network, which gave rise to the vesicular ducts. The latter fused with the testicular efferent ducts and formed the spermatic ducts. Considering this fusion, when the sperm cells reached the spermatic ducts, the fluid produced at the seminal vesicle covered them. Histochemical studies evidenced the presence of neutral and acid glycosaminoglycans in the seminal fluid. Considering the reproductive behaviour of C. aeneus, it is believed that the protection associated with the immobilization of the sperm cells assures the sperm integrity during the passage through female's intestine until fertilization