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Embryology, Anatomy, and Physiology of the Kidneys and Ureters
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Paul Sturch, Sanjeev Madaan, Seshadri Sriprasad
This ureteric bud forms:The collecting system (collecting duct, CD), renal pelvis, and ureter.This process is known as renal induction.
Ureteric duplication
Published in Mark Davenport, James D. Geiger, Nigel J. Hall, Steven S. Rothenberg, Operative Pediatric Surgery, 2020
Sarah L. Hecht, Duncan T. Wilcox
Two developmental structures give rise to the mature human kidney and ureters; the ureteric bud, which develops into the collecting system and ureters, and the metanephros, which develops into the nephrons and renal parenchyma. The ureteric bud begins as an epithelial outpouching off the distal mesonephric (Wolffian) duct. Typically, there is a single ureteric bud on each side giving rise to bilateral single ureters. The ureteric bud grows into the metanephros and a process of reciprocal induction causes nephrogenesis and ureteral branching. The renal unit with its branched collecting system migrates cranially, and the ureter grows caudally to merge with the urogenital sinus (the eventual bladder). Once incorporated into the urogenital sinus, the ureteral orifice migrates in a cranial and lateral direction from the bladder neck to its orthotopic position on the trigonal ridge.
Renal, Cardiovascular, and Pulmonary Functions of Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
Embryonic development of the kidney depends on time-related reciprocal inductive signals between mesenchymal and epithelial progenitor tissues [1,2]. The urinary system is a component of the “urogenital system,” and is anatomically associated with genital development. Kidney development in humans begins early during embryonic life (weeks 5–6 of gestation), and progresses through three developmental stages: pronephros, mesonephros, and metanephros, to the end of gestation. The early patterning of the kidney region depends on interactions between the Pax/Eya/Six genes, with essential roles also played by lim1, Odd1, and Wnt genes. Ureteric bud outgrowth and branching morphogenesis are controlled by the Ret/Gdnf pathway, which is under positive and negative regulation by a variety of factors. After birth, the kidneys continue to mature, and by 2 years of age, they are similar to the adult kidneys in their capacity for regulating body water and for ensuring waste elimination. During childhood, the kidneys grow in size and reach a near-adult size of 10 cm in diameter by 12 years of age; the bladder also continues to grow up to this age.
Clinical Presentations and Diagnostic Imaging of VACTERL Association
Published in Fetal and Pediatric Pathology, 2023
Gabriele Tonni, Çağla Koçak, Gianpaolo Grisolia, Giuseppe Rizzo, Edward Araujo Júnior, Heron Werner, Rodrigo Ruano, Waldo Sepulveda, Maria Paola Bonasoni, Mario Lituania
In VACTERL, anatomical anomalies must occur between the 23rd and 56th day post-conception, as this embryological window is critical for the development of the vertebrae (23-32 days), heart, tracheoesophageal structures, forearm bones (29-41 days), and anorectal region (45-56 days). Malsegmentation of the vertebrae is the result of timing abnormalities in the segmentation clock. Anorectal and tracheoesophageal defects are due to disturbed mesodermal proliferation and migration, epithelial-mesenchymal interactions, and apoptosis. Radial aplasia can be caused by impairment in laying down, condensing, or chondrifying the angle of the radius. Renal and urinary tract anomalies may be the result of failed growth of the ureteric bud, metanephric mesenchyme, and mesonephros/mesonephric duct. Cardiac defects involve altered cardiac septal development, as atrioventricular septal defects and tetralogy of Fallot defects are common [13].
Connection of ES Cell-derived Collecting Ducts and Ureter-like Structures to Host Kidneys in Culture
Published in Organogenesis, 2021
The connection of one ureteric bud derivative to another is not a feature of natural UB/collecting duct ureter development. The entire ureter and collecting duct system develop by branching morphogenesis from the UB, with no need for any connections to be made and with no evidence of connections ever being made. Indeed, the branches of the growing tree show mutual repulsion.12 Within the kidney, however, nephrons are required to make a connection between their distal pole and the collecting duct branch that induced their formation in the first place.16 It may be that the need to perform this connection, the mechanisms of which are still not understood in detail, means that UB-derived epithelia retain an innate ability to make connections that generate open-lumen communications between the tubules involved.
Advances in understanding vertebrate nephrogenesis
Published in Tissue Barriers, 2020
Joseph M. Chambers, Rebecca A. Wingert
The mammalian metanephros contains two well-characterized renal progenitor populations: the metanephric mesenchyme (MM) and the ureteric bud (UB) (Figure 1). The UB derives from the nephric duct and gives rise to the collecting duct system, and the MM is the source of all nephron lineages and contains vascular, stromal, and nephron progenitor cells (NPC). The UB initiates nephron induction by invading the MM and undergoes progressive branching after receiving reciprocal signals from the MM. Occurring simultaneously, UB signals cause the MM to condense around the ureteric tips forming a structure termed the cap mesenchyme (CM), which retains the Six2+ Cited1+ NPC population. The NPCs border the ureteric epithelium and other cell populations are more distant from this site. Recent lineage-tracing studies have begun to appreciate how position, movement, and spatial exposure to differentiation cues can determine self-renewal or differentiation status within NPC pools. For example, a subset of Wnt4-expressing cells was discovered to migrate back to nephron progenitor zone and exhibit plasticity regarding nephron commitment25