摘要:

AbstractLight and electron microscopy of the excretory kidney of adolescent dogfish,Scyliorhinus caniculus(L.), revealed immature and mature nephrons as well as four developmental stages of nephrons. At stage I the nephron was characterized by a condensed mass of mesenchymal cells in the center of several concentric layers of connective tissue. At stage II of the nephron, the S‐shaped body was an elongate cyst with a high prismatic epithelium that was connected by a developing collecting tubule with the collecting duct system. At stage III, the developing nephrons already possess the essential features of the mature nephron but lack complete differentiation. Developing renal corpuscles had one afferent arteriole and two efferent vessels. Developing tubules ran four times between the lateral bundle zone and the mesial tissue zone before they joined the collecting duct system. A continuous sheath of flat cells, encompassing the collecting duct system, extended around the developing lateral bundle. A rudimentary central vessel ran from the developing lateral bundle to the venous sinusoid capillaries between the mesial convolutions. Developmental stage IV was similar to the mature nephron, however, renal corpuscles and tubular segments were smaller than those of mature nephrons.Conclusive evidence for morphological homology of elasmobranch nephron segments and collecting tubule‐collecting duct system with those of other vertebrates is provided. The origin and nature of the central vessel and the bundle sheath is clarified. These specific structures of marine elasmobranch kidney supposedly are of great functional relevance for the renal countercurrent system that in turn is essential for ion‐ and osmoregul

ISSN:0002-9106    

DOI:10.1002/aja.1001900402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractCiliated vacuoles and intraepithelial cysts have been observed in oviductal and endocervical epithelia of rabbits. In this study, rabbits under various hormonal conditions were studied by light and transmission electron microscopy and tissue culture in an attempt to determine their distribution and origin. Ciliated vacuoles most frequently lay in the basal cytoplasm, below or beside the nucleus, and very close to the basal lamina. A few were apically located. Their average diameter was 8.8 by 5.1 μm. Cilia and microvilli projected into the vacuolar lumen. These vacuoles were located intracellularly as evidenced first by the degeneration of both their cilia and microvilli and the moderately dense matrix that often filled the vacuolar lumen, as observed by electron microscopy. Secondly, phase microscopy of the living endocervical epithelium allowed us to observe the beating of the cilia within the vacuoles, not on the surface of such cells. Thirdly, ruthenium red stained the surface glycocalyx of the ciliated and secretory cells, but not that of the cilia and microvilli within the vacuoles.The intraepithelial cysts were not observed in all tissue blocks. The largest numbers were found in ovariectomized animals treated for 3 and 5 days with estradiol. More were seen in the isthmus and cervix than in the fimbria and ampulla. The cysts were located most often within the epithelium along the sides of, and at the bases of, the mucosal folds. They were lined by flattened epithelium of various combinations of secretory and ciliated cells.An unusual cell type was associated with some of the cysts and ciliated vacuoles. Its cytoplasm contained aggregates of mitochondria and vesicles whose contents varied in density. Although the genesis of the ciliated vacuoles is not certain, our results indicate that they may arise from aberrant positioning of proliferating procentrioles or from a defect in targeting or transporting the centrioles to the apical plasma membrane to serve as basal bodies. Fusion of adjacent ciliated vacuoles with lumina lined by secretory cells having deep apical invaginations appeared to contribute to the formation of cysts

ISSN:0002-9106    

DOI:10.1002/aja.1001900403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe goat epididymis, based on morphological differences, was divided into five regions; regions I and II, and the proximal part of region III constituted the head; the distal part of region III and region IV, the body; and region V, the tail. The epithelium of all regions contained principal and basal epithelial cells and intraepithelial lymphocytes and macrophages. In addition, regions II to IV also contained a few apical cells. Clear cells were absent.The epithelium varied in height from the tallest in region I (88 ± 33 μm) to the shortest in region V (38 ± 5 μm). Conversely, the luminal diameter, thickness of smooth muscle wall, and luminal sperm concentration were highest in region V. The irregular epithelial height of regions I and IV accounted for a stellate lumen in contrast to the oval lumen of the other regions. Whereas the lumen of region I contained only a few sperm, those of regions II, III, and IV were filled with sperm.Principal cells were the only cell type that showed striking cytological differences between regions. While they contained absorptive features (canaliculi, pinocytotic and coated vesicles, and subapical vacuoles) in all regions, the principal cells of region II were filled with large, heterogeneous vacuoles (up to 5 μm in diameter), suggesting that they may be preferentially involved in transporting and digesting particulate material. Besides absorptive features, principal cells of all regions contained morphological correlates of protein synthesis such as highly developed Golgi complexes in the supranuclear area and numerous cisternae of RER near the Golgi body and in the infranuclear cytoplasm. The cisternae of RER were more developed in region IV, and in some instances, they were distended with flocculent material resembling newly synthesized protein. Unlike the protein synthesizing organelles, principal cells of all regions lacked morphological correlates of steroid hormone synthesis.These results are compared with previously published data on the regional differences in the epididymis of other species, especially with those of the rat and the bull, in an effort to understand the significance of the epididymis in sperm matura

ISSN:0002-9106    

DOI:10.1002/aja.1001900404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe morphological innervation pattern of developing fetal and neonatal rabbit hearts was delineated histochemically by a cholinesterase/silver procedure and immunohistochemically with the monoclonal antibody HNK1, an antibody which recognizes some cells derived from neuroectoderm. Cholinesterase‐containing nerves appeared distally on the outflow tract by gestational day 15 (G15). Isolated cells with cholinesterase‐stained fine processes were present near the base of the pulmonary trunk. HNK1 antibody stained the same nerves and ganglia revealed by the cholinesterase reaction and other nerves in the rabbit heart. It was used to confirm that cells with fine neuron‐like processes were present before nerve ingrowth. The G14 heart contained many HNK1 staining cells in the right atrium, outflow, and inflow tracts; cells with fine processes were few but increased at G16. By G17, a plexus of interweaving nerves and associated cells began to form at the base of the pulmonary trunk. Fine nerves encircled the base of the aorta, and others crossed the intercaval region dorsally. At G19, nerves (1) extended downward from a rich “bulbar” plexus along the front ventricular surface, (2) grew near the epicardial surface at the base of the heart along the atrial floor and ventricular roof, (3) traversed the vena cavae and intercaval region to enter the atrial roof, and (4) crossed the coronary sinus to reach the back ventricular walls. By G23, cholinesterase‐staining nerves and ganglia in the atria and, epicardially, in the ventricles formed the general innervation pattern of the newborn and adult r

ISSN:0002-9106    

DOI:10.1002/aja.1001900405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe anatomy of the human trapezius muscle is complex, with an extensive origin and fibers running in different directions. The muscle is commonly divided into three different muscle portions according to the fiber direction: the descending, transverse, and ascending portions. In a previous study in males, the structure of the muscle differed between different portions with respect to the enzyme‐histochemical fibertype profile. The lower regions of the descending portion and the transverse and the ascending portions had a predominance of type I fibers. The type II fibers were more frequent in the upper regions of the descending portion, and the cross‐sectional fiber area in this region of the muscle was smaller. In this study, we have investigated the trapezius muscle in females and compared the results with those from males. The different portions of the female muscle had a relatively even fiber‐type composition. However, there tended to be fewer type I fibers and more type IIB fibers in the descending portion of the muscle, and the fibers of the lower regions of the descending portion were somewhat larger. The fiber‐type distribution pattern was similar to that of the male trapezius muscle, but the mean cross‐sectional area of the fibers in the female muscle was considerably smaller. Thus, our conclusion is that the trapezius muscle of females has a similar activity pattern as that of males. The significantly smaller cross‐sectional fiber area, however, may indicate a lower functional capacity which may be of importance in the development of neck and shoulder dysfunction

ISSN:0002-9106    

DOI:10.1002/aja.1001900406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001900401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY