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1.
对凹耳臭蛙Odorrana tormota消化系统进行了解剖学及组织学观察。消化道可以分为口腔、咽、食道、胃、十二指肠、回肠和直肠,末端开口于泄殖腔。肝脏和胰腺为消化腺。消化道管壁的组织结构均为4层结构,由管腔向外依次为黏膜层、黏膜下层、肌层和浆膜。胃黏膜层中含有许多胃腺,可明显分为腺颈部和腺体部。小肠含有十二指肠腺,直肠含有直肠腺。肝脏发达,分为左、中、右3叶,肝小叶界限不明显。胰腺中的腺泡由腺细胞围成。凹耳臭蛙肠全长与头体长之比为0.44~0.91,是迄今为止报道的无尾两栖类中最小的。  相似文献   

2.
  总被引:2,自引:0,他引:2  
The estimated mean intestinal coefficients of Leporinus friderici Bloch, 1794 and L. taeniofasciatus Britski, 1997, from the Upper Tocantins River, central-western Brazil, were 1·25±0·15 and 1·14±0·07, respectively. The external surfaces of the lips have taste buds. The histological structure is composed of four layers: mucosa, submucosa, muscular, and serosa. No muscularis mucosa is detected. The oesophageal epithelium is stratified in L. friderici and pseudostratified in L. taeniofasciatus , the latter with PAS+ basal cells and eosinophilic apical cells. A thick layer of adipose tissue was found within the submucosa. Leporinus taeniofasciatus has a sphincter separating the cardiac and fundic portions of the stomach. In both species, gastric glands are present in the stomach, except in its pyloric portion. The pyloric caeca possess a simple columnar epithelium with brush border and three types of goblet cells. Rodlet cells were found in L. friderici . The three portions of the intestine showed no histological differences. Anatomical and histological features of the digestive tract are consistent with the omnivorous habit of both these species.  相似文献   

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The alimentary canal of the two‐spot ladybird Adalia bipunctata (Linnaeus) (Coleoptera: Coccinellidae) presents the foregut (stomodeum), the midgut (mesenteron) and the hindgut (proctodeum). The shortest region is the foregut and the longest is the midgut. The relative proportions of the main regions were found to be similar for males and females. In the foregut it was possible to distinguish the pharynx, the esophagus and the proventriculus but no crop. The hindgut is composed of the ileum, rectum and rectal canal. Generally the organ width is similar for males and females, but females presented a wider proventriculus. The epithelium of the foregut varied from squamous to simple cuboidal and columnar. In the midgut the epithelium is simple columnar with goblet and regenerative cells. The epithelium of the hindgut varied from simple cuboidal to squamous. Females presented thicker midgut epithelium whereas males presented thicker epithelium in the esophagus. The anatomy of the alimentary canal of A. bipunctata seems to conform to its carnivorous and recent phylogenetic status within the family Coccinellidae.  相似文献   

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Two secretary birds and three Kori bustards were studied to determine differences between their body size and gastrointestinal morphology. Body measurements were made on captive, live birds and gastrointestinal measurements on fresh postmortem specimens. For predator species, such as the Kori bustard and secretary bird, body size is a function of their ability to capture and destroy prey. While the secretary bird was clearly the taller of the two species, superior body weight, wing length, and therefore body size was noted for the Kori bustard. The size and length of the gastrointestinal tract varied between species. The secretary bird had the shorter, less complex digestive tract, with a foregut well adapted for consumption of large quantities of flesh. The large intestine was devoid of ceca. The gastrointestinal tract of the Kori bustard was markedly different from that of the secretary bird. The foregut was less complex and the large intestine possessed large, voluminous ceca.  相似文献   

6.
米志平  杨智 《四川动物》2001,20(4):214-216
小熊猫的胃属单室腺型胃,它以角切迹为界,可分为胃底部和幽门部两部分。胃壁由粘膜、粘膜下层、肌层和浆膜四层组成。四上皮为单层柱状上皮,具有分泌粘液的功能。胃腺有贲门腺、胃底腺、幽门腺三种,但贲门腺不发达。主细胞、壁细胞和粘液细胞的数量与分布呈现规律性变化。肌层发达,特别是内环行肌发达。并与大熊猫胃的结构作了比较。  相似文献   

7.
王智 《生物资源》2023,45(4):348-354
本文对鸟类哈氏腺的解剖学、组织学及生理功能的研究进展进行了综述,对其未来的研究方向进行了展望,以期为此领域的研究提供参考。大多数鸟类哈氏腺的形态大体上无实质性差异,最常见的与家鸡相似:形状不规则,腺体被一层薄的结缔组织包膜隔成不同的小叶。根据小叶结构和排列在腺泡及小管的上皮细胞种类,鸟类哈氏腺可分为三类,即复管泡状腺,复管状腺和混合型腺,复管泡状腺中家鸡为代表,复管状腺中家鸭为代表,混合型中秃鼻乌鸦(Corvusfrugilegus)为代表。腺体结构的类型可能与鸟类习性和行为有关。鸟类哈氏腺除最基本的润滑角膜和瞬膜功能外,还是B细胞活化和终末分化以及浆细胞增殖的场所,作为外周免疫器官,与脾脏、法氏囊和盲肠集合淋巴样组织一起构成决定鸟类全身和局部免疫反应的器官系统。  相似文献   

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Hybodontoid and nonhybodontoid sharks are described from the Lower Triassic Vega‐Phroso Siltstone Member of Sulphur Mountain Formation on the basis of newly discovered material. The age of the classic fossil site ‘Wapiti Lake’ in the Canadian Rocky Mountains is discussed on the basis of new field data and one conodont found in association. Preliminary results suggest that these elasmobranch remains are between early Smithian and Spathian in age. Apart from the enigmatic genus Listracanthus and previously reported edestoids, the shark fauna consists of at least one hybodont, at least two questionable hybodontoid genera and an elasmobranch of enigmatic affinities, represented by peculiar denticles only and described as ‘genus A’incertae sedis. The presence of the only previously reported hybodont genus, cf. Palaeobates, is erroneous. The largest specimen represents the most complete Early Mesozoic shark known. The heterodonty of its dentition, fin spine morphology and the short, robust body shape imply it represents a member of a new family of shark, Wapitiodidae fam. nov. , and is described here as Wapitiodus aplopagus gen. et sp. nov. The unique dental morphology shows affinities to Polyacrodus but clearly differs in the complete lack of side cusps. Wapitiodus gen. nov. possesses a primitive fin spine structure. The tooth crowns are entirely blunt in the distal (posterior) tooth files, and are acuminate‐unicuspid in several anterior files. Tooth morphology, the shape of the basal cartilages, the proximal insertion of the fin spines and the pectoral fin structure are interpreted as diagnostic characters for this new genus, and possibly for the Wapitiodidae fam. nov. The majority of observed characters appear to be primitive and are reminiscent of Palaeozoic sharks, however, and these features include dorsal fin spine morphology and gross skull anatomy. A second species, provisionally placed in the same genus, is described as Wapitiodus homalorhizo sp. nov. Wapitiodus homalorhizo sp. nov. can be distinguished from W. aplopagus gen. et sp. nov. by the proportions of the fin spines, tooth morphology and possibly the body shape. Several isolated teeth and other fragmentary material are referred to either Wapitiodus gen. nov. sp. indet. or to ?Polyacrodus sp. (Polyacrodontidae gen. et sp. indet.). A third genus of elasmobranch (incertae sedis) is described as ‘Genus A’ and is recognized by its peculiar scales. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 149 , 309–337.  相似文献   

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To better understand the mating systems of majoid crabs, we studied the functional anatomy of the female reproductive systems of the spider crabs Leurocyclus tuberculosus and Libinia spinosa, comparing them with those of other Majoidea. Adult females were measured and dissected, and their reproductive systems described macroscopically and histologically. In females of both species, the seminal receptacles are paired globular structures of ecto‐mesodermal origin. The mesoderm‐derived region is lined by a stratified epithelium. The anchoring, proliferative, and secretory strata are clearly recognizable . The ectoderm‐derived region is lined by a simple cylindrical epithelium underlying a cuticle that increases in thickness toward the vagina. The transition between the ectoderm and mesoderm‐derived regions is abrupt, with differences between the studied species: Li. spinosa has a “velum,” whereas Le. tuberculosus presents prominent “folds.” In both species, the position in which the oviduct is connected to the seminal receptacles is intermediate between the dorsal and ventral types previously described in other eubrachyurans. The seminal receptacles of the studied species show four different conditions, which can be distinguished macroscopically based on their shape and amount of sperm stored. We compare our data with those from other Majoidea in an attempt to determine whether the morphology of the seminal receptacles is related to different mating strategies or behaviors.  相似文献   

10.
运用解剖学和组织学方法对宽体金线蛭消化道的结构进行了组织学研究。结果表明,宽体金线蛭的嗉囊向两侧伸出11对侧盲囊,第6对侧盲囊狭长并延伸到直肠两侧;咽主要由黏膜层、肌层和外膜构成,外膜几乎不可见;食道、嗉囊、肠和直肠管壁由黏膜层、黏膜下层、肌层和浆膜构成;咽和直肠的上皮具纹状缘。除肠外,其他消化道的上皮细胞均无发达的纤毛,且黏膜上皮皆为单层柱状上皮;除肠和直肠外,腺体及导管较少;直肠的黏膜肌层为内环外纵两层,其他各部均为纵行肌一层;消化道各部黏膜下层较发达;外膜为浆膜,与黏膜下层分界不明显。  相似文献   

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Male salamanders use nephrons from the genital kidney to transport sperm from the testicular lobules to the Wolffian duct. The microstructure of the epithelia of the genital kidney proximal tubule and distal tubule was studied over 1 year in a population of Notophthalmus viridescens from Crawford and Pike counties in central Missouri. Through ultrastructural analysis, we were able to support the hypothesis that the genital kidney nephrons are modified to aid in the transportation of sperm. A lack of folding of the basal plasma membrane, in both the genital kidney proximal and distal tubules when compared to the pelvic kidney proximal and distal tubules, reduces the surface area and thus likely decreases the efficiency of reabsorption in these nephron regions of the genital kidney. Ciliated epithelial cells are also present along the entire length of the genital kidney proximal tubule, but are lacking in the epithelium of the pelvic kidney proximal tubule. The exact function of these cilia remains unknown, but they may aid in mixing of seminal fluids or the transportation of immature sperm through the genital kidney nephrons. Ultrastructural analysis of proximal and distal tubules of the genital kidney revealed no seasonal variation in cellular activity and no mass production of seminal fluids throughout the reproductive cycle. Thus, we failed to support the hypothesis that the cellular activity of the epithelia lining the genital kidney nephrons is correlated to specific events in the reproductive cycle. The cytoplasmic contents and overall structure of the genital and pelvic kidney epithelial cells were similar to recent observations in Ambystoma maculatum, with the absence of abundant dense bodies apically in the epithelial cells lining the genital kidney distal tubule. J. Morphol. 275:914–922, 2014. © 2014 Wiley Periodicals, Inc.  相似文献   

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The ducts associated with sperm transport from the testicular lobules to the Wolffian ducts in Ambystoma maculatum were examined with transmission electron microscopy. Based on the ultrastructure and historical precedence, new terminology for this network of ducts is proposed that better represents primary hypotheses of homology. Furthermore, the terminology proposed better characterizes the distinct regions of the sperm transport ducts in salamanders based on anatomy and should, therefore, lead to more accurate comparisons in the future. While developing the above ontology, we also tested the hypothesis that nephrons from the genital kidney are modified from those of the pelvic kidney due to the fact that the former nephrons function in sperm transport. Our ultrastructural analysis of the genital kidney supports this hypothesis, as the basal plasma membrane of distinct functional regions of the nephron (proximal convoluted tubule, distal convoluted tubule, and collecting tubule) appear less folded (indicating decreased surface area and reduced reabsorption efficiency) and the proximal convoluted tubule possesses ciliated epithelial cells along its entire length. Furthermore, visible luminal filtrate is absent from the nephrons of the genital kidney throughout their entire length. Thus, it appears that the nephrons of the genital kidney have reduced reabsorptive capacity and ciliated cells of the proximal convoluted tubule may increase the movement of immature sperm through the sperm transport ducts or aid in the mixing of seminal fluids within the ducts. © J. Morphol., 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

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We studied the morphology of the copulatory organ of Ortalis canicollis and its evolution in birds. The phallus of O. canicollis is intromittent, with a blind tubular cavity and two distinct regions when erect: the base of the phallus, which shows the mucosa smooth and lined by a pseudostratified columnar epithelium, and the tubular portion, which shows the mucosa lined by a keratinized stratified squamous epithelium with little knobs. The phallus includes two vascular bodies at the cranial portion in the urodeum. A fibrocartilaginous body anchors the tubular portion therefrom up to the eversible portion. A branched elastic ligament inserts on different regions of the tubular portion. The phallus is plesiomorphic in birds and it has disappeared in Megapodius, Leipoa and Neoaves. The asymmetric phallus evolved early and it was retained in the basal branches of birds. The intromittent phallus is plesiomorphic in birds (found in Archosauria's ancestor), but Crypturellus, Numididae, Odontophoridae and Phasianidae have developed a non‐intromittent phallus a posteriori. The blind tubular cavity and the fibrocartilaginous body evolved as an adaptive convergence many times in birds. Therefore, this study shed some light on morphological aspects of the phallus and contributed to understand its evolution in birds.  相似文献   

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After experimental infection with simian immunodeficiency virus (SIV), intestinal endoscopy proved to be an easily tolerated, minimal invasive procedure to obtain biopsies from the gastrointestinal tract of rhesus macaques during all stages of disease. As the GI tract is affected by many opportunistic infections and immunological impairment after SIV/human immunodeficiency virus (HIV) infection, knowledge on the proviral load is an important parameter for a better understanding of disease pathogenesis. In this paper, we describe the set-up and evaluation of a quantitative competitive polymerase chain reaction (PCR) and the quantification of SIV intestinal proviral load in a long-term follow-up study of eight rhesus monkeys ( Macaca mulatta ) after two different routes of virus inoculation. A SIV-specific signal could be detected as early as day 3 after infection. Of 143 biopsies from the follow-up study, 85.3% showed a positive PCR. DNA copy numbers ranged from 300 to 15,000 molecules per 100,000 cells. No significant influence of the inoculation route could be shown on either proviral load or survival time, but higher SIV proviral load was associated with a more rapid progression to disease. Therefore, the amount of proviral load in intestinal biopsies may be an important prognostic value for the further course of the disease.  相似文献   

18.
小鼠胃肠道嗜银细胞的分布及形态学观察   总被引:2,自引:0,他引:2  
用Grimelius嗜银法对10只小鼠胃肠道嗜银细胞的分布及形态学作了观察研究,结果显示:(l)小鼠嗜银细胞的分布密度,在胃体部最高,从十二脂肠、空肠、回肠、盲肠直到结肠依次减少。(2)嗜银细胞的形态也是多种多样,有梭形、锥体形、椭圆形等。  相似文献   

19.
人体组织解剖学是高等师范院校生物系的一门基础课。为了提高该学科的教学效果,笔者认为教师要更新教学理念,实施素质教育;注重非智力因素培养,促进学生智力发展;改革教学方式,注重启发式、探究式教学;分流教学内容,降低教学难度;革新教学手段,注重多媒体教学;改革实验教学,开设综合性、设计性实验;指导学生开展科研活动,提高大学生的综合素质和创新能力。  相似文献   

20.
Pericarp histology in the Oncospermatinae reveals distinctive characters at the generic level but no unique characters at the subtribal level. Pericarp structure is diverse but parallels the diversity found in other subtribes of the Areceae. The subtribe appears to be divisible into two distinct groups: one in which sclereids alone provide the primary protective barrier in the outer fruit and one in which fibrous bundles, some-times in combination with brachysclereids, form the outer barrier. This division of the subtribe supports similar conclusions derived from morphological data.  相似文献   

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