Maturation of the gastric microvasculature in Xenopus laevis (Lissamphibia, Anura) occurs at the transition from the herbivorous to the carnivorous lifestyle, predominantly by intussuceptive microvascular growth (IMG): a scanning electron microscope study of microvascular corrosion casts and correlative light microscopy
نویسندگان
چکیده
The microvascular bed of the stomach of Xenopus laevis and the changes it undergoes when the herbivorous tadpole becomes a carnivorous adult were studied by scanning electron microscopy of vascular corrosion casts and light microscopy of stained tissue sections. In tadpoles an upper and a lower gastric artery supplied, and upper, middle and lower medial and lateral gastric veins drained the vertically extending stomach. During metamorphosis, the stomach gained a horizontal cranio-caudal extension and vessels accordingly become dorsal and ventral gastric arteries, and anterior, middle and posterior gastric veins, respectively. Up to stage 64 (late climax) mucosal capillaries formed a polygonal network of wide immature-looking capillaries ensheathing gastric glands in a basket-like manner. From stage 64 onwards, blood vessels of the stomach appeared mature, revealed a clear hierarchy and were correlated closely with the histomorphology of the stomach, which had also gained the adult pattern. Within the gastric mucosa, ascending arterioles branched in a fountain-like pattern into wide subepithelial capillaries establishing a centripetal blood flow along the gastric glands, which makes an ultrashort control loop of glandular cells within the branched tubular gastric glands very unlikely. Formation of the stomach external muscular layer started at stage 57 when smooth muscle cells locally formed a single longitudinal and one-to-two single circular layers. Abundant signs of intussusceptive microvascular growth and rare vascular sprouts in vascular corrosion casts indicated that the larval-to-adult microvascular pattern formation of the stomach of Xenopus laevis Daudin occurs predominantly by non-sprouting angiogenesis.
منابع مشابه
Microvascular anatomy of the large intestine in adult Xenopus laevis: scanning electron microscopy of vascular corrosion casts and correlative light microscopy.
The microvascular anatomy of the large intestine of the adult South African Clawed Toad, Xenopus laevis (Daudin), was studied by scanning electron microscopy (SEM) of vascular corrosion casts (VCCs) and correlative light microscopy. Observations showed the large intestine to be supplied by the haemorrhoidal artery and the posterior mesenteric artery and drain via the posterior haemorrhoidal vei...
متن کاملO-10: A Marked Animal-Vegetal Polarity in The Localization of Na+,K+-ATPase Activity and Its Down-Regulation Following Progesterone-Induced Maturation
Background: Polarized cells are key to the process of differentiation. Xenopus oocyte is a polarized cell that has complete blue-print to differentiate 3 germ layers following fertilization, as key determinant molecules (Proteins and RNAs) are asymmetrically localized. The objective of this work was to localize Na+, K+-ATPase activity along animal-vegetal axis of polarized Xenopus oocyte and fo...
متن کاملMorphological and histochemical investigation of the camel (Camelus dromedarius) abomasal mucous membrane by light and scanning electron microscopy (SEM)
Morphological and histochemical study of the abomasal epithelium in camel (Camelus dromedarius) wascarried out by light and scanning electron microscopes. The lining of the abomasum was divided into fourregions, i.e. cardiac, pseudocardiac, fundic and pyloric. Our investigation revealed that the cardiac andpseudocardiac regions occupy a wide part of the abomasum in camel and it reaches approxim...
متن کاملScanning electron microscopy of vascular corrosion casts--standard method for studying microvessels.
Scanning electron microscopy (SEM) of vascular corrosion casts (microvascular corrosion casting/SEM method) is a standard method, which allows three-dimensional visualization with good resolution of the normal and abnormal microvessels, including the capillaries of various organs and tissues. SEM of vascular corrosion casts can obtain qualitative as well as quantitative informations important t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 87 شماره
صفحات -
تاریخ انتشار 2012