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1.
白鲟消化道形态学与组织学的初步观察   总被引:13,自引:0,他引:13  
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。  相似文献
2.
鲇的消化能力与营养价值分析   总被引:8,自引:1,他引:7       下载免费PDF全文
采用常规方法测定了鲇(Silurusasotus)的消化道指数,其比肠长、比胃重、比肠重、比肝胰脏重和比内脏重分别为0726±0087、0027±0015、0013±0008、0022±0004和0081±0041。体重与体长的回归方程Y=00124X2.8451(r=09940,P<001);鲇的胃、前肠、中肠和后肠中消化液的pH值分别为48~62、66~70、69~75、72~77,且消化道各部分具有较高的蛋白酶和淀粉酶活性,蛋白酶的活性为前肠>胰脏>胃>中肠>后肠;而淀粉酶的活性则为胰脏>胃>前肠>中肠>后肠;肌肉中粗蛋白的含量1881%,粗脂肪含量152%;必需氨基酸含量占氨基酸总量的4451%,鲜味氨基酸含量占氨基酸总量的4598%,综合肌肉的常规营养成分和氨基酸分析的结果,鲇是一种营养价值较高的优质鱼类。  相似文献
3.
七种白蚁消化道解剖形态的比较研究   总被引:3,自引:0,他引:3  
张方耀  唐觉 《昆虫知识》1994,31(5):300-302
本文对采自浙江省的7种白蚁(东方原白蚁,黄肢散白蚁,黑胸散白蚁,肖若散白蚁,家白蚁,杨之江近歪白蚁和和大鼻象白蚁)的消化道形态进行了解剖比较研究。并初步探讨了白蚁消化道形态在白蚁系统发育和进化中的意义。  相似文献
4.
In the holothurian Eupentacta fraudatrix,the gut wall exhibits trilaminar organization. It consists of an inner digestive epithelium, a middle layer of connective tissue, and an outer mesothelium (coelomic epithelium). The pharynx, esophagus, and stomach are lined with a cuticular epithelium composed of T-shaped cells. The lining epithelium of the intestine and cloaca lacks a cuticle and consists of columnar vesicular enterocytes. Mucocytes are also encountered in the digestive epithelium. The connective tissue layer is composed of a ground substance, which houses collagen fibers, amoebocytes, morula cells, and fibroblasts. The gut mesothelium is a pseudostratified epithelium, which is dominated by peritoneal and myoepithelial cells and also includes the perikarya and processes of the neurons of the hyponeural plexus and vacuolated cells.  相似文献
5.
We correlated available fate maps for the avian neural plate at stages HH4 and HH8 with the progress of local molecular specification, aiming to determine when the molecular specification maps of the primary longitudinal and transversal domains of the anterior forebrain agree with the fate mapped data. To this end, we examined selected gene expression patterns as they normally evolved in whole mounts and sections between HH4 and HH8 (or HH10/11 in some cases), performed novel fate-mapping experiments within the anterior forebrain at HH4 and examined the results at HH8, and correlated grafts with expression of selected gene markers. The data provided new details to the HH4 fate map, and disclosed some genes (e.g., Six3 and Ganf) whose expression domains initially are very extensive and subsequently retract rostralwards. Apart from anteroposterior dynamics, some genes soon became downregulated at the prospective forebrain floor plate, or allowed to identify an early roof plate domain (dorsoventral pattern). Peculiarities of the telencephalon (initial specification and differentiation of pallium versus subpallium) are contemplated. The basic anterior forebrain subdivisions seem to acquire correlated specification and fate mapping patterns around stage HH8.  相似文献
6.
The regeneration of the epithelial lining of the stomach of the brittle star Amphipholis kochii after autotomy of the aboral part of the disk was studied. It was shown that a part of the stomach epithelium remained after autotomy. Its cells participated in regeneration of the epithelium during restoration of the lost digestive system. There was a partial dedifferentiation of the epithelium cells of stomach, their migration and proliferation; cells of the stomach retained some specialized cytoplasmic structures, secretory vacuoles, and pinocytic vesicles. Migration of ectodermal cells of the esophagus in the damaged area was also recorded.  相似文献
7.
8.
We performed a TEM study of regeneration of the intestine in the Far Eastern trepang, the holothurian Apostichopus japonicus, after evisceration. The following stages were distinguished in the restoration process of the digestive tube: the growth of connective tissue along the margin of the mesenterium, in the place of rupture; dedifferentiation of cells and their migration and proliferation; the rooting of the esophagus lining into the connective tissue anlage; and the transformation of esophagus cells into cells of the middle part of the intestine. The migration of epithelium into the area of regeneration takes place through a solid cellular layer, without breaking of the cell contacts. The mitotic activity was registered in all stages of restoration; the dividing cells were located chaotically, without the development of a blastema.  相似文献
9.
草鱼(Ctenopharyngodon idellus)是我国主要的淡水养殖经济鱼类之一,其食性随着生长发育而改变,能利用植物性和动物性两类饵料。草鱼幼鱼期食性分为三个阶段:浮游动物食性、食性转变阶段和草食性。草鱼食性在其早期发育中变化很大。动物性饵料,如浮游动物、底栖无脊椎动物是早期生长发育阶段重要的饵料成分;随着草鱼的生长,浮游甲壳动物和摇蚊幼虫则成为较重要  相似文献
10.
运用Grimelius银染法对菲牛蛭(Poecilobdella manillensis)消化管内嗜银细胞的分布和形态进行观察,并根据嗜银细胞的分布特点统计其分布密度.消化管除食道外各部位均有嗜银细胞分布,细胞染棕色或黑色;嗜银细胞基本位于上皮细胞之间和固有层内,主要呈圆形、椭圆形、锥体形和长条形等多种形态;部分细胞胞突明显,细胞内可见黑色分泌颗粒.嗜银细胞分布密度为颚片最高,嗉囊次之,直肠最低,食道内未检测出嗜银细胞.消化管各段嗜银细胞的形态特征和分布规律可能与其食性和消化生理活动密切相关.  相似文献
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