pronephric

• adj.

• 前腎の

関

pronephros

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/08/05 17:53:38」(JST)

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Pronephros
Details
Carnegie stage	10
Days	20
Precursor	nephrotome
Gives rise to	mesonephros
Identifiers
Code	TE E5.6.1.0.0.0.1
Anatomical terminology [edit on Wikidata]

Pronephros the most basic of the three excretory organs that develop in vertebrates, corresponding to the first stage of kidney development. It is succeeded by the mesonephros, which in fish and amphibians remains as the adult kidney. In amniotes the mesonephros is the embryonic kidney and a more complex metanephros acts as the adult kidney. Once a more advanced kidney forms, the previous version typically degenerates by apoptosis or becomes part of the male reproductive system.

The pronephros develops from the intermediate mesoderm, as do the later kidneys. It is a paired organ, consisting of a single giant nephron that processes blood filtrate produced from glomeruli or glomera- large embryonic glomeruli. The filtrate is deposited into the coelom. It then passes through thin ciliated tubules into the pronephric nephron where it is processed for solute recovery.

The organ is active in adult forms of some primitive fish, like lampreys or hagfish. It is present at the embryo of more advanced fish and at the larval stage of amphibians where it plays an essential role in osmoregulation. In human beings, it is rudimentary, appears at the end of the third week (day 20) and replaced by mesonephros after 3.5 weeks. Despite this transient appearance in mammals, the pronephros is essential for the development of the adult kidneys. The duct of the mesonephros forms the Wolffian duct and ureter of the adult kidney. The embryonic kidney and its derivatives also produces the inductive signals that trigger formation of the adult kidney.

Development

The pronephros is the first in a sequence of kidneys that form in vertebrate embryos. The pronephric primordium develops from the intermediate mesoderm, lying between the paraxial (somitic) mesoderm and the lateral plate. In many organisms (e.g. amphibians) this primodium forms anteriorly then migrates posteriorly to fuse with the cloaca, while in others it forms along the length of the intermediate mesoderm (e.g. aritra ghosh)...

Drainage

In both amphibians and zebrafish the pronephros has a single nephron attached to a nephric duct, which in turn is linked to the cloaca. Although these kidneys have a simple anatomical organization with only a single nephron, the nephrons have a segmental and functional complexity that is very similar to that in more complex kidneys such as mesonephroi and metanephroi.

Filtration

One unique feature of pronephroi is the arrangement by which the glomerular filtrate is generated and collected by the nephron. In pronephroi the glomerulus (or glomus if it extends over multiple body segments) projects into the coelom rather than into the proximal tip of the nephron. The glomerular filtrate flows directly into the coelom, or a dorsal compartment of the coelom known as the nephrocoel. In jawless fishes, the pronephric glomus projects into the pericardial cavity. Fluids are swept from the filtration cavity into the nephron through cilated funnels known as nephrostomes. These thin epithelial tubes are densely packed with cilia and have a distinct morpology to the other tubular epithelia of the kidney.

Relationship to nephrotomes

Older anatomical texts describe the pronephros as condensing from nephrotomes, but modern visualization techniques have shown that this represents a histological artifact.

In amphibians, fishes, and mammals

Once the more complex mesonephros forms the pronephros undergoes apoptosis in amphibians. In fishes the nephron degenerates but the organ remains and becomes a component of the immune system.

In mammals a functional pronephros, in the context of an organ performing waste excretion or osmoregulation, does not develop. However, a kidney primordium that runs along the intermediate mesoderm does form and links up to the cloaca. This duct is known as the pronephric duct, mesonephric duct or Wolffian duct. While this transient primordium never forms functional nephrons, the duct derived from it is essential to the development of the more complex later kidneys.

See also

• Mesonephros
• Metanephros

External links

• Development of the pronephros in zebrafish

English Journal

• Knockdown of Tmem234 in zebrafish results in proteinuria.

• Rodriguez PQ1, Oddsson A2, Ebarasi L3, He B2, Hultenby K4, Wernerson A5, Betsholtz C6, Tryggvason K7, Patrakka J8.
• American journal of physiology. Renal physiology.Am J Physiol Renal Physiol.2015 Dec 1;309(11):F955-66. doi: 10.1152/ajprenal.00525.2014. Epub 2015 Sep 16.
• Podocytes are highly specialized epithelial cells located at the outer aspects of the glomerular capillary tuft and critical components of the kidney filtration barrier. To maintain their unique features, podocytes express a number of proteins that are only sparsely found elsewhere in the body. In t
• PMID 26377798

• Evaluation of nephrotoxic effects of aristolochic acid on zebrafish (Danio rerio) larvae.

• Wang X1, Liu KC2, Sun GJ3, Han LW1, Wang RC1, Peng WB1, Sun C1, Hsiao CD4, Zhang Y1, Hou HR1.
• Human & experimental toxicology.Hum Exp Toxicol.2015 Nov 26. pii: 0960327115613844. [Epub ahead of print]
• To analyze the toxic effects of aristolochic acid (AA) on developed kidneys in zebrafish larvae, zebrafish at 3 days postfertilization were treated with various concentrations of AA for 24 h before the status of kidney injury was investigated from several points of view. It was found that 21% of the
• PMID 26612554

• Arl13b and the exocyst interact synergistically in ciliogenesis.

• Seixas C1, Choi SY2, Polgar N3, Umberger NL4, East MP5, Zuo X2, Moreiras H6, Ghossoub R7, Benmerah A8, Kahn RA5, Fogelgren B3, Caspary T4, Lipschutz JH9, Barral DC1.
• Molecular biology of the cell.Mol Biol Cell.2015 Nov 18. pii: mbc.E15-02-0061. [Epub ahead of print]
• Arl13b belongs to the ADP-ribosylation factor (Arf) family within the Ras superfamily of regulatory GTPases. Mutations in Arl13b cause Joubert syndrome (JS) characterized by congenital cerebellar ataxia, hypotonia, oculomotor apraxia, and mental retardation. Arl13b is highly enriched in cilia and is
• PMID 26582389

Japanese Journal

• Evaluation of the teratogenic effects of three traditional Chinese medicines, Si Jun Zi Tang, Liu Jun Zi Tang and Shenling Baizhu San, during zebrafish pronephros development

• Journal of Toxicologic Pathology 28(3), 141-149, 2015
• NAID 130005090417

• Evaluation of the teratogenic effects of three traditional Chinese medicines, Si Jun Zi Tang, Liu Jun Zi Tang and Shenling Baizhu San, during zebrafish pronephros development

• Journal of Toxicologic Pathology advpub(0), 2015
• NAID 130005069587

• Inhibition of stored Ca^<2+> release disrupts convergence-related cell movements in the lateral intermediate mesoderm resulting in abnormal positioning and morphology of the pronephric anlagen in intact zebrafish embryos

• Development, growth & differentiation 51(4), 429-442, 2009-05-01
• NAID 10025376114

Related Links

• Pronephric duct - Wikipedia, the free encyclopedia

The pronephric duct is the predecessor of the Wolffian duct. [edit] Development. The development of the pronephric duct is a part of the development of the urinary and reproductive organs. In the outer part of the intermediate mesoderm, ...

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