青蛙食管和胃中肌肉分布的光学显微镜研究。

Laboratory of Biology, Kanagawa Prefectural College of Nursing and Medical Technology, Yokohama, Japan.

J Smooth Muscle Res. 2001 Aug;37(3-4):95-104. doi: 10.1540/jsmr.37.95.

The present study reports light microscopical observations of the distribution of muscle in the esophagus and stomach of both the bull frog (Rana catesbeiana) and the African clawed frog (Xenopus laevis). The external muscle coat of the upper half of the esophagus in both species had several collagen coated bundles of striated muscle fibres around the circumference. These striated muscle bundles ran longitudinally from the pharynx to around the vicinity of the center of the esophagus. Beneath these striated muscle bundles was an inner circular layer of smooth muscle. In both species, the inner circular layer of smooth muscle was particularly thick in the region close to the pharynx. In the bull frog, the lower half of the esophagus lacked striated muscle. However, the circular smooth muscle layer, extending from the upper half of the esophagus, was also observed throughout the lower half of the esophagus. An outer longitudinal layer of smooth muscle developed towards the terminal portion of the esophagus such that in this region, both outer longitudinal and inner circular layers of smooth muscle were observed. Similarly in the African clawed frog, the inner circular layer of smooth muscle was continuous along the full length of the esophagus. Again, no striated muscle bundles were observed in the lower half of the esophagus. However, the outer longitudinal layer of smooth muscle was seen to develop in the middle region of the esophagus. Its muscle layer extended to the terminal portion of the esophagus. Thus, both outer longitudinal and inner circular layers of smooth muscle were observed throughout the lower half of the esophagus. In both frogs, the thickness of the outer longitudinal and inner circular layers of smooth muscle changed before and after the esophago-gastric junction. In both frogs, no muscularis mucosa was observed in the esophageal wall. However, in the lower half of the esophagus of the African clawed frog, small bundles of smooth muscle were observed here and there in the submucosa. A fully developed muscularis mucosa with both outer longitudinal and inner circular layers was observed in the upper stomach of both frogs.

本研究报告了对牛蛙（牛蛙）和非洲爪蟾（非洲爪蟾）食管和胃中肌肉分布的光学显微镜观察结果。两种物种食管上半部分的外部肌层在圆周周围有几束有胶原包裹的横纹肌纤维。这些横纹肌束从咽部纵向延伸至食管中心附近。在这些横纹肌束下方是一层内环行平滑肌。在两种物种中，靠近咽部的区域内环行平滑肌层特别厚。在牛蛙中，食管下半部分没有横纹肌。然而，从食管上半部分延伸而来的环行平滑肌层在食管下半部分也可见。一层外纵行平滑肌向食管末端发展，因此在该区域观察到了外纵行和内环行平滑肌层。同样，在非洲爪蟾中，内环行平滑肌层沿食管全长连续。同样，在食管下半部分未观察到横纹肌束。然而，在食管中部区域可见外纵行平滑肌层发展。其肌层延伸至食管末端。因此，在食管下半部分观察到了外纵行和内环行平滑肌层。在两种蛙中，食管-胃交界处前后外纵行和内环行平滑肌层的厚度发生了变化。在两种蛙中，食管壁均未观察到黏膜肌层。然而，在非洲爪蟾食管下半部分的黏膜下层各处观察到了小束平滑肌。在两种蛙的胃上部均观察到了具有外纵行和内环行两层的完全发育的黏膜肌层。