Microvascular anatomy of the esophagus in larval and adult Xenopus laevis Daudin: a scanning electron microscope study of microvascular corrosion casts and correlative light microscopy

Abstract

AbstractLarval to adult microvascular anatomy of the esophagus was studied in the South African Clawed Toad, Xenopus laevis (Daudin) by scanning electron microscopy of vascular corrosion casts and correlative light microscopy of paraplast embedded stained tissue sections. Analyses of vascular corrosion casts of tadpole esophaguses at premetamorphosis revealed a wide‐meshed, but mature looking capillary bed which during following prometamorphosis increased in density and gained the adult‐like pattern during late metamorphic climax by sprouting and nonsprouting angiogenesis. In adult Xenopus, the esophageal mucosa possessed a dense subepithelial capillary bed fed by one or two esophageal arteries that originated from right and/or left thoracic aorta just distal to the origin of the subclavian arteries. In the adult undistended esophagus, esophageal arteries revealed an undulating course, a pattern that guarantees a continuous blood supply when the esophagus is extremely wide expanded as it is the case when adult Xenopus swallows large prey.