RESUMO
The secretion of the subcommissural organ (SCO) is synthesized in the intrinsic cells of that structure, a neuroendocrine gland. The organelles involved in the synthesis of this secretion are rough-surfaced endoplasmic reticulum (RER) and the Golgi apparatus. It is still uncertain whether and to what extent the latter participates in the synthesis. In highly active secretory ependymal cells of the SCO, the Golgi apparatus exhibits distinct signs of intense activity. This suggests that the Golgi apparatus is involved in the preparation of the secretion, even if this is difficult to prove electron microscopically. The secretion is discharged from the optical part of the SCO-cells into the cerebrospinal fluid (CSF) of the IIIrd ventricle, where Reissner's fibre is formed. Different phases of release of the content of the secretory granula into the IIIrd ventricle are described; our findings are in agreement with previously published observations. In 2 cases delicately granulated and moderately electron-dense material was found in circumscriptly dilated vaults of the intercellular spaces. Release of secretory material into intercellular spaces appears to be possible, but is evidently infrequent. Regular occurrence of a basal (peripheral) discharge into the hypendymal capillaries is not unanimously agreed upon as yet. In this paper, a passage of granula is described from the cytoplasm of the end feet of SCO cells through the walls of the capillaries into the systemic circulation. This provides structural evidence that secretory material synthesized in the SCO is released into the capillaries. These observations must ultimately be confirmed with the aid of ultracytochemical methods, particularly using labelled material.
Assuntos
Haplorrinos/fisiologia , Sistemas Neurossecretores/metabolismo , Órgão Subcomissural/metabolismo , Animais , Callithrix/anatomia & histologia , Callithrix/fisiologia , Callitrichinae/anatomia & histologia , Callitrichinae/fisiologia , Cebus/anatomia & histologia , Cebus/fisiologia , Retículo Endoplasmático/ultraestrutura , Feminino , Complexo de Golgi/ultraestrutura , Haplorrinos/anatomia & histologia , Masculino , Microscopia Eletrônica , Microvilosidades , Saimiri/anatomia & histologia , Saimiri/fisiologia , América do Sul , Especificidade da Espécie , Órgão Subcomissural/citologiaRESUMO
Solenodon paradoxus possesses a proboscis-like, elongated rostrum which is very motile. The rhinarium is remarkable because of its distinctly developed sulci limitantes, sulcus medianus rhinarii, and postnarial hairless integumental pads topographically similar to the crenated folds found in Setifer and Echinops. Rhinarial glands are also present. The sulcus medianus proboscidis (rhinarii) is continuous with the vestibulum oris. Integumental folds affixing the upper lips to the gum are absent, as are the labial part of the sulcus rhinarii and the sulcus papillae palatinae. The anatomical condition of the proboscis and the anterior part of the palate cannot be considered primitive in a phylogenetic sense, because it is essentially different from the situation found in Didelphys, Tupaia, and the lemuriform primates. The vomeronasal organ is in direct communication with the nasal cavity; there is no communication with the ductus nasopalatinus or with the oral cavity. In contrast to Didelphys, Tupaia, and the prosimians so far studied, the nasal cavity opens directly through the nasopalatine duct into the oral cavity proper. These differences are likely to be of taxonomic and phylogenetic significance, although definite conclusions in this regard should not be drawn until the respective conditions of the other insectivores have been studied.
Assuntos
Eulipotyphla/anatomia & histologia , Nariz/anatomia & histologia , Animais , Células Quimiorreceptoras , Haiti , Boca/anatomia & histologia , Nariz/fisiologia , Filogenia , Especificidade da EspécieRESUMO
This is a preliminary study on the comparative microscopic anatomy of the external noses of platyrrhine monkeys. Platyrrhinism is caused by the lateral width of the internarium (Alar cartilages, soft tissue in the sulcus interalaris covered by the integument). The septum nasi, situated caudal to the internarium is not involved in platyrrhinism. Aotus and Alouatta are, according to the definition, truely playtrrhine. The division of the higher primates into Platyrrhina and Catarrhina is justified. The anterior surface of the internarium (sinus hairs) is a sensorial area.