ABSTRACT
The hammerhead sharks shows a head laterally expanded with eyes and nostrils on the edges, which gives the species a hammer appearance. Another strand of studies indicates that the hypothesis of head shape alterations for better adaptions in the sensorial system with the development of structures associated to binocular sight and others sensorial organs. Given the variety of characteristics, the study aim was to describe the anatomical constitution of the hammerhead shark eye bulb. The bulb and its annexes exenteration was performed, and further dissection; the morphological description of the muscle insertions and eye bulb components were based on direct observation and were further photographed and catalogued. The eye bulb fragments and its annexes were histological technical. Between the sclera and the choroid it was possible to observe, by the electronical scanning microscopy, the thin layer called supra-choroid, in this region, spaces often filled by lymphatic vessels allied to a matrix formed by loose conjunctive tissue are found. In the choroid, a layer which is rich in blood vessels, loose conjunctive tissue and collagen fibers, was observed, besides pigmentary cells full of melanin in its interior, which result in its layer's dark color. Ciliary body is a choroid's dilatation; it has the aspect of a thick ring in finger-like shape, pigmented, covering the sclera surface and containing pigmentary cells. The crystalline capsule, which shows an acellular covering that, is hyaline and homogeneous. In the electronical scanning microscopy, it was observed that the capsule is extremely thick especially in the anterior face. The capsule is very elastic, constituted mainly by thin lamellae of collagenous fibers, as illustrated by the electronically scanning microscopy. Anatomic variations related mainly to the position of the eye bulb in the skull, fibrous tunica and lens call the attention and must be related to its habitat.
El tiburón martillo tiene la cabeza lateralmente expandida con los ojos y la nariz en sus márgenes. Estudios indican que alteraciones de la forma de la cabeza de estos animales son adaptaciones que mejoran el desarrollo del sistema sensorial y estructuras asociadas a la visión binocular y otros órganos sensoriales. Dada la variedad de características, el objetivo del estudio fue describir la constitución anatómica del bulbo ocular. Se disecó el bulbo ocular junto a sus anexos. La descripción morfológica de las inserciones musculares y componentes del bulbo ocular se basaron en la observación directa, siendo éstas fotografiadas y catalogadas. Entre la esclera y la coroides se observó através de microscopía electrónica de barrido, una delgada capa supra-coroides, y vasos linfáticos junto a la matriz formada por tejidos conectivos. La coroides, era abundante en vasos sanguíneos y fibras de tejido conectivo. Se observaron escasas células pigmentarias llenas de melanina, lo que se asemeja a un anillo en forma de dedo, de manera que cubren la superficie de la esclera y células que contienen pigmentos. En la cápsula del lente, fue posible observar un recubrimiento celular, hialino y homogéneo. En la microscopía electrónica de barrido, se observó una cápsula muy gruesa, principalmente en la región frontal. La cápsula elástica,estaba constituida por láminas delgadas, principalmente, por fibras de colágeno. Se concluyó que el bulbo ocular de estos animales posee variaciones anatómicas relacionadas, principalmente, con la posición del bulbo ocular en el cráneo, túnica fibrosa y lente, lo que puede estar directamente relacionado con su hábitat.
Subject(s)
Animals , Eye/anatomy & histology , Sharks/anatomy & histology , Eye/ultrastructure , Microscopy, ElectronABSTRACT
Abstract Considering the physiological importance and need of greater morphophysiological knowledge of adrenal glands, the aims of present study were compare the morphometric data between left and right adrenal of male and female; perform a histological, scanning and transmission electron microscopy study showing tissue constitution of glands; finally, in order to define the presence and correct site of the cytochrome P450c17 expression in adrenal glands, immunohistochemical study of this enzyme was performed in 18 adrenal glands (right n=9 and left n=9) of nine adult Galea spixii (four males and five females). Right adrenal was more cranially positioned than left adrenal; dimensions (weight, length and width) of right adrenal was larger than left adrenal; no differences between male and female body and adrenal measurements were found; the morphology of cells and different amounts of lipid droplets may be related to the different demands of steroid hormones production, related to each zone of the adrenal cortex; and, the cytochrome P450c17 immunolocalization in fasciculate and reticular zone may be related with synthesis of 17-hydroxy-pregnenolone, 17-hydroxy-progesterone, dehydroepiandrosterone or androstenedione.
Resumo Considerando a importância fisiológica e a necessidade de melhor conhecimento morfofisiológico das glândulas adrenais, os objetivos do presente estudo foram comparar dados morfométricos entre adrenais direitas e esquerdas de machos e fêmeas; realizar estudos histológicos e microscopia eletrônica de varredura e transmissão revelando a constituição tecidual das glândulas; finalmente, foi realizado estudo imunohistoquímico com objetivo de definir a presença e correto sítio de expressão da citocromo P450c17 nas glândulas adrenais em 18 glândulas adrenais (direita n=9 e esquerda n=9) de nove Galea spixii adultos (quatro machos e cinco fêmeas). A glândula adrenal direita estava posicionada mais cranialmente que a adrenal esquerda; as dimensões (peso, comprimento e largura) da glândula adrenal direita foram maiores que as da esquerda; não houve diferença entre as medidas corpóreas e das adrenais entre machos e fêmeas; a morfologia das células e diferentes quantidades de gotículas lipídicas podem estar relacionadas a diferentes demandas na produção de hormônios esteroides relacionados a cada zona do córtex adrenal; e, a imunolocalização da citocromo P450 na zona fasciculada e reticular pode estar relacionado com a síntese de 17-hidroxi-pregnenolona, 17-hidroxi-progesterona, dehidroepiandrosterona ou androstenediona.