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Embryology, Anatomy, and Physiology of the Bladder
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Allan Johnston, Tarik Amer, Omar Aboumarzouk, Hashim Hashim
The cloaca is the terminal portion of the embryonic hindgut:Lined with endoderm.Forms a pit in contact with the embryonic surface ectoderm (proctodeum/anal pit).Receives the allantois ventrally.Divided into a dorsal and ventral part by the urorectal septum (Figure 10.1).
The British School: Caiman, Cannon, and Manton and their effect on carcinology in the English speaking world
Published in Frank Truesdale, History of Carcinology, 2020
Cannon soon discovered that some muscles in the anostracan Chirocephalus actually differentiated from ectoderm — those associated with the presumptive proctodeum fold inward with proctodeal invagination and function as hindgut dilators. In addition, Cannon noted that the ventral muscles attached to the endoskeleton also arose from involuted material derived from ectoderm. Cannon’s subsequent studies on the development of segmental structures, especially those associated with transient coelomic pouches, earned him a solid reputation as an experimental zoologist, and garnered for him in quick succession a D.Sc. from the University of London and election to the chair of zoology at the University of Sheffield in 1926, and fellowship in the Royal Society and the awarding of the Linnean Society Crisp Medal in 1927 — all by the age of 30.
The digestive system and the respiratory system
Published in Frank J. Dye, Human Life Before Birth, 2019
A large part of the colon and the rectum have their origins in the hindgut (Figure 16.6). The caudal end of the hindgut is a blind tube ending at the cloacal membrane, the boundary between the rectum and the proctodeum (an inpocketing of ectoderm on the ventral side of the tail end of the embryo). The portion of the hindgut near the cloacal membrane is called the cloaca. From the cloaca's ventral surface, the allantoic diverticulum extends for a short distance into the umbilical cord. The urorectal septum grows between the hindgut and allantoic diverticulum toward the cloacal membrane, separating the cloacal membrane into an anal membrane and a urogenital membrane (see Figure 16.6). When the anal membrane ruptures during the seventh week, the anus opens to provide a passageway from the digestive tube into the amniotic fluid.
Iron nanoparticle bio-interactions evaluated in Xenopus laevis embryos, a model for studying the safety of ingested nanoparticles
Published in Nanotoxicology, 2020
Patrizia Bonfanti, Anita Colombo, Melissa Saibene, Luisa Fiandra, Ilaria Armenia, Federica Gamberoni, Rosalba Gornati, Giovanni Bernardini, Paride Mantecca
For light microscopy analyses, embryos were randomly selected at the end of the FETAX assays, fixed in 10% buffered formalin and processed for embedding in paraffin. The samples were transversely cut from eye to proctodeum into 6 μm thick serial sections, and mounted on glass slides. Sections were alternatively stained with hematoxylin and eosin (H&E) for histopathological analysis and Prussian blue or Turnbull staining for evidencing tissue Fe(III) or Fe(II) deposits. Sections were finally examined with a Zeiss Axioplan light microscope, equipped with an Axiocam MRc5 digital camera. Ten specimens for each experimental group were histologically screened.