香鱼消化道及肝脏的形态结构特征

采用解剖及石蜡切片显微技术观察了香鱼消化道及肝脏的组织学结构。香鱼消化道由口咽腔、食道、胃及肠构成。口咽腔大且狭长,其底壁前部有一对粘膜褶,两颌边缘着生宽扁梳状齿,腭骨及舌骨具齿,犁骨无齿;舌由基舌骨突出部分覆盖粘膜构成,舌粘膜上皮为复层扁平上皮,含有较多的杯状细胞和味蕾。食道、胃及肠均由粘膜层、粘膜下层、肌层及外膜构成。食道粘膜层上皮为复层扁平上皮,杯状细胞发达。胃呈V形,由贲门部、胃体部及幽门部组成,胃壁粘膜上皮为单层柱状上皮,贲门部与胃体部的固有层中有胃腺。肠较短,由前、中、后肠构成,肠壁粘膜上皮为单层柱状上皮,其游离面具微绒毛;上皮细胞间有杯状细胞。幽门盲囊有350～400条,其组织学结构与肠相同。肝脏单叶,外被浆膜;肝细胞形态不规则,肝小叶界限不明显。     

广东乌龟消化道组织学观察

采用常规石蜡切片法,观察了广东乌龟的食道、胃、小肠和大肠的组织结构.结果发现,这四种器官都是由粘膜层、粘膜下层、肌层和外膜组成,各部分的差别主要在于粘膜层和肌层.食道和大肠上皮为复层柱状上皮:胃和小肠上皮为单层柱状上皮.食道粘膜上皮特化形成与呼吸有关的绒毛.胃有大量胃腺,腔面有纵行皱襞.小肠表面有大量绒毛,在绒毛中可见肠腺.大肠具粘膜皱襞和较多的杯状细胞,无绒毛,可见许多分散的淋巴小结.胃和肠道肌肉为内环外纵,内环肌较厚,外纵肌较薄.     

商城肥鲵消化道的解剖学观察

该文首次报道了商城肥鲵消化道各部分的形态结构、长度及其组织学结构。结果表明,除口腔外,消化道管壁由粘膜层、粘膜下层、肌层和浆膜层构成,消化道各部分的差别主要在粘膜层和肌层食道粘膜为复层柱状上皮,食完纵肌层,胃、肠粘膜上皮为单层柱状上皮,胃、肠肌层由内环外纵两层平滑肌组成。粘膜上皮的皱褶程度、腺体分布情况、肌层的相对厚度等在消化道各部分也存在差异。     

文县疣螈消化道和肝脏的形态学及组织学观察

利用生物显微技术对文县疣螈的消化道和肝脏进行了观察.结果 表明:文县疣螈的消化道管壁由粘膜层、粘膜下层、肌层和外膜组成.食管粘膜为复层扁平柱状上皮,胃、小肠和直肠上皮为单层柱状上皮.各段皱褶丰富.胃有发达的腺体,肠的各段无多细胞腺体分布.杯状细胞丰富,其中十二指肠最少,直肠部最多,胃的各部无杯状细胞.肝小叶分界不清,肝...     

版纳鱼螈消化道解剖学和组织学观察

对我国特有珍稀濒危两栖动物版纳鱼螈(Ichthyophis bannanicus)的消化道进行解剖和组织学观察.结果表明,版纳鱼螈消化道呈直管状,无盘曲;胃、肠分化明显,肠可分为十二指肠、空肠、大肠和直肠;黏膜上皮食管为复层柱状纤毛上皮,胃后段为单层柱状上皮,直肠为复层扁平上皮,其余均为复层柱状上皮;口咽腔黏膜含大量巨型杯状细胞,有单泡状颌间腺;食道中下段有团泡状食道腺;胃体部含大量单管状胃腺;十二指肠和空肠有单泡状肠腺,绒毛发达;口咽腔的黏膜下层不明显,食道和直肠的黏膜下层为疏松结缔组织,其余均为细密的结缔组织;肌层除口咽腔为骨骼肌外,其余均为内环外纵两层平滑肌,其中,在十二指肠和空肠的两肌层间有细密的结缔组织连接.     

可口革囊星虫消化道的形态及组织学结构

对可口革囊星虫(Phascolosoma esculenta)消化道各部分结构进行了形态学和组织学观察,表明可口革囊星虫消化道由翻吻、咽、食道、肠、直肠和肛门组成。翻吻收缩性很强;肠道极长,沿纺锤肌螺旋缠绕成肠索。消化道管壁由内向外分为粘膜层、粘膜下层、肌层和外膜。粘膜上皮主要由柱状细胞组成。除肠外,消化道上皮细胞均有发达的纤毛,肠上皮细胞主要具发达的微绒毛;粘膜下层及肌层的发达程度因消化道的部位不同而异。     

高山倭蛙消化道结构初步观察

高山倭蛙食道粘膜上皮为复层柱状上皮,且固有膜中有丰富的复泡状腺;胃贲门部粘膜上皮无杯状细胞,PAS反应显示固有膜中有深红色颗粒分布,胃体中胃腺丰富;肠分为小肠、大肠、直肠3部分.小肠和直肠上皮中杯状细胞数量多.无尾类消化道结构与海拔高度无明显相关关系.     

巴西彩龟消化道组织学的初步观察

巴西彩龟的消化道管壁由内向外依次由粘膜、粘膜下层、肌层和浆膜4层结构组成.食管、胃和大肠有纵行粘膜皱襞,小肠无皱襞但有绒毛.食管上皮和肠上皮为复层柱状上皮,胃上皮为单层柱状上皮.消化道粘膜固有层内分布有淋巴细胞,虽然淋巴细胞有聚集现象,但没有形成典型的淋巴小结.无食管腺和肠腺,虽然有胃腺但胃腺细胞分化不明显,说明巴西彩龟消化道的组织分化程度较低,在系统发育中处于较低等地位.     

蜡皮蜥消化系统组织学初步研究（图版封3）

应用行蜡常规切片,HE染色,对蜡皮蜥的消化系统组织结构进行了观察。结果表明：消化道管壁除口咽腔外,其余由粘膜层、粘膜下层、肌层和浆膜层组成;不同部位的消化道管壁厚度各不相同,其中胃壁最厚,幽门胃壁厚达658．0μm,其次为大肠和食道,分别为393．3μm和215．9μm,小肠壁最薄,约为126．8μm皱襞的发达程度也随消化道的部位不同而有所差异,十二指肠皱襞数量最多,约为27～42个,平均高度为733.2μm,其次分别为回肠、口咽腔和食道,大肠皱襞数量最少约为3～11个,平均高度为484．2μm;食道上皮为复层鳞状上皮细胞,口咽腔、胃、小肠和大肠上皮均为单层柱状上皮;食道和大肠上皮的杯状细胞较多,密度分别为927个／mm^2、899个／mm^2;肝脏中色素细胞发达并含大量深色颗粒,胰脏泡心细胞较少且胰岛不发达,肝脏小叶和胰脏小叶界限不清晰。这充分说明了蜡皮蜥消化系统的组织结构特征与其食性和生态习性相适应,与鸟类和哺乳动物相比,具有一定的不完善性和低等性。     

白鲟消化道形态学与组织学的初步观察

白鲟消化道具有肉食性鱼类的典型特征,其口咽腔结构既适合捕食又适合吞食与滤食水生动物。咽后消化道可分为食道、胃后行支、胃前行支、小肠、瓣肠、直肠与肛门。幽门盲囊似一致密器官,小肠与瓣肠连接处有一特殊淋巴器官,肛门两侧有腹孔。白鲟口咽腔被覆层扁平上皮,上皮内有味蕾分布。咽后消化道组织分层为粘膜(无粘膜肌层)、粘膜下层(小肠及瓣肠前部无)、肌层与外膜。粘膜上皮为单层柱状上皮,由纤毛柱状细胞、一般柱状细胞和杯状细胞组成,其间还散在有颗粒细胞和游走细胞。食道后部与胃的一般柱状细胞为分泌粘液的细胞,肠内的一般柱状细胞为吸收细胞。胃后行支及部分前行支固有膜内有消化腺,其余各部的固有膜为致密层。小肠前中部粘膜形成蜂窝状粘膜窦,无肠腺。除食道前部肌层中有横纹肌外,其余部的肌层均为平滑肌。外膜内结缔组织有的致密有的疏松,外膜表面细胞柱状或立方形或扁平。     

Seasonal Morphological Changes in the Intestinal Digestive Epithelium of the Mussel Crenomytilus grayanus

Seasonal morphological changes in the intestinal digestive epithelium of the mussel Crenomytilus grayanus (Dunker) were studied. No changes in the cellular composition of the lining epithelium of the intestine were revealed during the annual cycle. Cyclic morphofunctional changes, including reduction of the height of the epithelium in summer and its hypertrophy in winter, increase in the number and size of the nucleoli, etc., were shown to occur.     

亚东鲑消化系统的形态学和组织学观察

亚东鲑消化系统包括消化道和消化腺。消化道分为明显的食道、胃和肠等。食道粘膜为复层上皮,其中含有杯状细胞和味蕾,胃、肠粘膜为单层柱状上皮,其中散布较多的杯状细胞。消化腺包括肝脏和胰腺,肝小叶分界明显,胰腺外分泌部由腺泡组成,内分泌部即胰岛分散存在于外分泌部之间。     

Engineering the rabbit digestive ecosystem to improve digestive health and efficacy

In rabbits, the bacterial and archaeal community of caecal ecosystem is composed mostly of species not yet described and very specific to that species. In mammals, the digestive ecosystem plays important physiological roles: hydrolysis and fermentation of nutrients, immune system regulation, angiogenesis, gut development and acting as a barrier against pathogens. Understanding the functioning of the digestive ecosystem and how to control its functional and specific diversity is a priority, as this could provide new strategies to improve the resistance of the young rabbit to digestive disorders and improve feed efficiency. This review first recalls some facts about the specificity of rabbit digestive microbiota composition in the main fermentation compartment, and its variability with some new insights based on recent molecular approaches. The main functions of the digestive microbiota will then be explained. Finally, some possible ways to control rabbit caecal microbiota will be proposed and a suitable timing for action will be defined.     

Temporal changes in digestive enzyme activities in the gastrointestinal tract of European eel (Anguilla anguilla) (Linneo 1758) following feeding

Changes occurring after feeding in the digestive enzyme activities of European eel were investigated to provide some insights into the digestive physiology of this fish. Total and specific proteases, amylase and lipase activities were measured using standard biochemical assays over a 24 h cycle in fed eels, compared to starved ones, under the same rearing conditions. In the gastrointestinal tract of fed eels quantitative changes started 4 h after feeding and continued later on; conversely, in starved eels enzyme activities remained unchanged over time. In fed eels, total and specific protease activities showed an overall increasing trend in the intestine, while in the stomach they progressively decreased to values 22–50% lower than those measured at the pre-feeding time; this behaviour probably reflected the progression of digesta along the intestinal tract. The prolonged secretory response of European eel to food ingestion proved its extended activity in the digestive process.     

北草蜥几种消化酶活力比较

应用酶学分析法测定了越冬后北草蜥胃、肠组织中蛋白酶、淀粉酶、纤维素酶的活力。结果表明 ,不同年龄、性别的北草蜥同一组织中消化酶活力有显著差异 ;不同地理种群的北草蜥同一组织中消化酶活力有显著差异 ;不同消化酶在北草蜥同一组织中的活力有显著差异 ;在北草蜥不同的组织中同一消化酶的活力有显著差异。说明北草蜥消化酶的活力与年龄、性别、部位和地理环境等因素有关 ,受食物组成、能量需求和遗传等因素的影响 ,产生了不同的酶活力和分布。这也说明生物长期适应环境 ,形成了不同的代谢水平     

A freeze-fracture study of the digestive tract of the parasitic nematode Trichinella

Freeze-fracture preparations of the esophagus and intestine of larvae and adults of the nematode Trichinella spiralis illustrate the distribution of intramembranous particles in membranes of a number of cell types, and several specializations were found. Esophageal glands are prominently linked by gap junctions, but gap junctions were not found between intestinal cells. Muscle cells of the esophagus have rectilinear arrays of particles, thought to be points of adherence of the muscles to the esophageal epithelium. Clusters of particles are associated with these arrays and particle-free areas (probably Z bodies) also occur. Intestinal cells have small particles in their microvilli, large particles in the cells' apical membranes, and intermediate size particles, similar to membranes of other cells, in the lateral and basal membranes. Apical smooth septate junctions and tricellular junctions occur between intestinal cells.     

Ontogeny of the digestive system and the profile of proteases in larvae of cachara (Pseudoplatystoma reticulatum Siluriformes: Pimelodidae) and its hybrid (Pseudoplatystoma corruscans × Pseudoplatystoma reticulatum)

The development of the digestive system and digestive proteases was studied in cachara (Pseudoplatystoma reticulatum) and its hybrid (P. reticulatum × Pseudoplatystoma corruscans) during the first 25 days after fertilization. Both groups presented a fast and similar development of the digestive system, and the unspecific alkaline protease profile suggested that the digestive capacity of hybrid larvae is higher than that of cachara after the last half of the studied phase. The activities of trypsin and chymotrypsin were similar and observed since the oocyte. These observations suggested that cachara and its hybrid has similar digestive capacity and digestive system development.     

The fine structure of Culicinomyces clavisporus invading mosquito larvae

Electron microscope observations were made of the Australian and U.S. strains of Culicinomyces clavisporus infecting mosquito larvae. The wall of the conidium is composed of an inner (primary) layer, an outer (secondary) layer, and an exterior coating of a mucopolysaccharide substance believed responsible for conidial adhesion to the host cuticle prior to germination and penetration. In some instances the wall of the conidium is ruptured during germination and new wall layers and mucoid coating form around the germ tube whereas in other specimens the conidial wall layers extend around the germ tube without fracturing. The most common invasion site is through the larval foregut following ingestion of conidia. The apex of the germ tube presses tightly against the surface of the foregut cuticle and the mucilaginous coating is stripped away. There is evidence to suggest that the host epicuticle, which disappears across the zone of contact with the germ tube, is utilized for nutrition of the invading fungus. A collar of cuticle forms around the germ tube apex and a narrow penetrant hyphae extends into the procuticle. It is believed that cuticular penetration is primarily enzymatic assisted by mechanical pressure. The penetrant hypha swells into an oval cell in the hypodermal region and vegetative hypha then invade the hemocoel. The cells of the hypodermis develop signs of degeneration presumably due to the secretion of toxic substances from the invading hyphae. Host reactions, involving melanization of the host tissues, are sometimes evident among the invading penetrant hyphae in the cuticle or in the hypodermal cells in contact with the fungus. Melanized capsules form around some of the hyphae within the hemocoel. These latter reactions do not directly involve host blood cells and are examples of “humoral encapsulation” similar to that described by other authors during invasion of pathogenic organisms into mosquito larvae and chironomid larvae.