Structure of the toad's urinary bladder as related to its physiology.
Structure of the toad's urinary bladder as related to its physiology.
复制标题
蟾蜍膀胱的结构与其生理学有关。
DOI：
10.1083/jcb.10.4.529
复制
发表时间：
1961-08
期刊：
影响因子：
--
通讯作者：
RASMUSSEN, H
中科院分区：
文献类型：
--
作者：
PEACHEY, L D;RASMUSSEN, H
用光镜和电镜观察了海蟾蜍膀胱的结构。覆盖膀胱粘膜表面的上皮厚度为3至10微米，由鳞状上皮细胞、杯状细胞和含有许多线粒体的第三类细胞组成，第三类细胞可能代表处于分泌周期早期阶段的杯状细胞。这种上皮由30至几百微米厚的固有层支撑，含有胶原纤维、平滑肌纤维束和血管。膀胱的浆膜表面被不完全的间皮覆盖。鳞状上皮细胞的细胞质数量远远超过其他类型的细胞，其组织方式具有上皮分泌细胞的特征。线粒体，光滑和粗糙表面的内质网，高尔基体，“多泡体”，和孤立的颗粒和囊泡存在。在上皮细胞游离表面的质膜下立即发现分泌颗粒，并且可以看到分泌颗粒与这些膜融合并释放其内容物，以促成仅在细胞的游离粘膜表面上发现的纤维表面涂层。在这些表面上的质膜之下是另外的细颗粒组分。侧膜和基膜严重褶皱，精细结构普通。上皮细胞通过终端杆装置紧密结合在一起并密封在一起，在膀胱腔附近只有0.02 mµ的间隔，以防止细胞之间的漏水。在体外实验中证明，穿过膀胱壁的水穿过上皮细胞的细胞质，并且不涉及囊泡运输机制。体外实验还表明，上皮细胞的基底（浆膜）表面对水是自由渗透的，而游离（粘膜）表面通常相对不可渗透，但当膀胱的浆膜表面用神经垂体激素处理时变得可渗透。在粘膜表面发现的渗透性屏障在结构上可以由位于质膜外部的丝状层、由在质膜正下方发现的细胞内颗粒组分或由粘膜表面复合物的这两种组分来表示。强调上皮片的极性，并与两栖动物水平衡机制中膀胱的生理作用有关。
The structure of the urinary bladder of the toad Bufo marinus was studied by light and electron microscopy. The epithelium covering the mucosal surface of the bladder is 3 to 10 microns thick and consists of squamous epithelial cells, goblet cells, and a third class of cells containing many mitochondria and possibly representing goblet cells in early stages of their secretory cycle. This epithelium is supported on a lamina propria 30 to several hundred microns thick and containing collagen fibrils, bundles of smooth muscle fibers, and blood vessels. The serosal surface of the bladder is covered by an incomplete mesothelium. The cytoplasm of the squamous epithelial cells, which greatly outnumber the other types of cells, is organized in a way characteristic of epithelial secretory cells. Mitochondria, smooth and rough surfaced endoplasmic reticulum, a Golgi apparatus, "multivesicular bodies," and isolated particles and vesicles are present. Secretion granules are found immediately under the plasma membranes of the free surfaces of the epithelial cells and are seen to fuse with these membranes and release their contents to contribute to a fibrous surface coating found only on the free mucosal surfaces of the cells. Beneath the plasma membranes on these surfaces is an additional, finely granular component. Lateral and basal plasma membranes are heavily plicated and appear ordinary in fine structure. The cells of the epithelium are tightly held together by a terminal bar apparatus and sealed together, with an intervening space of only 0.02 mµ near the bladder lumen, in such a way as to prevent water leakage between the cells. It is demonstrated in in vitro experiments that water traversing the bladder wall passes through the cytoplasm of the epithelial cells and that a vesicle transport mechanism is not involved. In vitro experiments also show that the basal (serosal) surfaces of the epithelial cells are freely permeable to water, while the free (mucosal) surfaces are normally relatively impermeable but become permeable when the serosal surface of the bladder is treated with neurohypophyseal hormones. The permeability barrier found at the mucosal surface may be represented, structurally, either by the filamentous layer lying external to the plasma membrane, by the intracellular, granular component found just under the plasma membrane, or by both of these components of the mucosal surface complex. The polarity of the epithelial sheet is emphasized and related to the physiological role of the urinary bladder in amphibian water balance mechanisms.