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Origin and development of the pronephros in the chick embryo
Author(s) -
Hiruma Tamiko,
Nakamura Hiroaki
Publication year - 2003
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1046/j.1469-7580.2003.00245.x
Subject(s) - pronephros , intermediate mesoderm , mesoderm , biology , lateral plate mesoderm , mesonephros , anatomy , mesonephric duct , ingression , kidney development , embryo , primordium , duct (anatomy) , microbiology and biotechnology , embryogenesis , endocrinology , kidney , gastrulation , embryonic stem cell , zebrafish , genetics , gene
The process by which the pronephros develops was morphologically examined in chick embryos from Hamburger–Hamilton stage (ST) 8+ to ST34. The intermediate mesoderm, from which the pronephros arises, was first seen as a faint ridge of undifferentiated mesoderm between the segmental plate and lateral plate at ST8+. It formed a cell cord at the level of the 6th to the presumptive 13th somites at ST9 to ST10. This cell cord then separated into dorsal and ventral parts, the former becoming the nephric duct and the latter the tubules by ST14. The primordia of the external glomeruli (PEGs) appeared at ST15 through some epithelial cells protruding in the nephrostome (the opening of the nephric tubule into the body cavity). PEGs formed gradually in the caudal direction until ST18, while the pronephric tubules and PEGs in cranial locations disappeared. At this stage, only a few PEGs remained at the level of the 13th and 14th somites and these developed from ST23 to ST29 to become ultrastructurally similar to the glomeruli of the functional kidney. From these observations in the avian pronephros, we infer that the pronephric duct and tubules both form from a cell cord in the intermediate mesoderm and at the same time, but later develop differently.