Renal System Development

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Contents

Introduction

The paired adult kidneys filter blood, excrete waste, reabsorb water and have endocrine functions. In the embryo, there are several stages in their development closely linked to genital development. The nephron, the functional unit of the kidney, is also a classical epithelial/mesenchyme type of interaction. The functional unit of the kidney is the nephron and the process of their initial formation is called nephrogenesis. Each adult kidney typically contains about 750,000 nephrons, though the total number can vary significantly from as few as 250,000 to as many as 2,000,000.[1][2]

The urinary system is developmentally and anatomically associated with genital development, often described as the "urogenital system". (More? Genital System Development)


Renal Links: Introduction | Lecture - Renal Development | Urinary Bladder | Stage 13 | Stage 22 | Fetal | Renal Movies | Stage 22 Movie | Histology | Abnormalities | Category:Renal
Historic Embryology: 1907 Urogenital images | 1921 Urogenital Development | 1917 Urogenital System | 1926 Embryo 22 Somites

Some Recent Findings

Cloacal septation model[3]
  • Bmp7 functions via a polarity mechanism to promote cloacal septation[4] "During normal development in human and other placental mammals, the embryonic cloacal cavity separates along the axial longitudinal plane to give rise to the urethral system, ventrally, and the rectum, dorsally. Defects in cloacal development are very common and present clinically as a rectourethral fistula in about 1 in 5,000 live human births. Yet, the cellular mechanisms of cloacal septation remain poorly understood. ...Our results strongly indicate that Bmp7/JNK signaling regulates remodeling of the cloacal endoderm resulting in a topological separation of the urinary and digestive systems. Our study points to the importance of Bmp and JNK signaling in cloacal development and rectourethral malformations."
  • Size and location of the kidneys during the fetal period[5] "The level of the left kidney was higher than the level of the right kidney in the fetal period. The posterior surface relations to the ribs showed certain ascendance during gestation, corresponding to vertebral levels. However, fetal kidneys do not reach the same level as adults at full term. The kidneys move farther apart from the midline of the body during the fetal period. The dimensions, weight, and volume of the kidneys increased with gestational age during the fetal period. The ratio between kidney weights and fetal body weights were determined, and we observed that the ratio decreased during the fetal period. There were no sex or laterality differences in any parameter." (See also Fetal Development)
  • Characterization of Mesonephric Development and Regeneration Using Transgenic Zebrafish. [6] "The majority of previous studies have focused on the pronephros of zebrafish, which consists of only two nephrons and is structurally simpler than the mesonephros of adult fish and the metanephros of mammals. To evaluate the zebrafish system for more complex studies of kidney development and regeneration, we investigated the development and post-injury regeneration of the mesonephros in adult zebrafish." (See also Zebrafish Development)

Objectives

Stage 13 kidney sections.jpg
  • Understand the 3 main stages of kidney development.
  • Understand development of the nephron and renal papilla.
  • Brief understanding of the mechanisms of nephron development.
  • Understand the development of the cloaca, ureter and bladder.
  • Brief understanding of abnormalities of the urinary system.

Textbook References

  • The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Moore and T.V.N Persaud - Moore & Persaud Chapter 13 p303-346
  • Larsen’s Human Embryology by GC. Schoenwolf, SB. Bleyl, PR. Brauer and PH. Francis-West - Chapter 10 p261-306

Renal Movies

Renal Development

Urogenital sinus 001 icon.jpg
 ‎‎Renal Overview
Page | Play
Renal 001 icon.jpg
 ‎‎Nephron
Page | Play
Urogenital septum 001 icon.jpg
 ‎‎Urogenital Septum
Page | Play
Trigone 001 icon.jpg
 ‎‎Trigone
Page | Play
Stage13-GIT-icon.jpg
 ‎‎Gastrointestinal
Page | Play
Stage22-CNS-icon.jpg
 ‎‎Urogenital
Page | Play
Renal blood 01 icon.jpg
 ‎‎Renal Vascular
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Background

Early fetal kidney (week 10)
  • Mesoderm then intermediate mesoderm
  • Vascular Development
  • Gastrointestional
  • Cloacal development
  • Endocrine - covered in future lecture/lab

Kidney Anatomy

Adult nephron structure
Nephron histology
  • Nephron - Functional unit of kidney
  • Humans up to 1 million
  • Filtration of waste from blood
  • Endocrine
  • Blood pressure regulation

The key structure of the adult nephron is the glomerulus (renal corpuscle), which represents the initial vascular/renal interface.

Related Images: Nephron histology overview | glomerulus structure | vascular and renal poles


Ureter

  • Bladder - Urine storage
  • Endoderm allantois

Mesoderm

  • Intermediate mesoderm - Lies between somites and lateral plate

Intermediate Mesoderm

  • development occurs laterally symmetrical (left right)
  • intermediate mesoderm lying beside the dorsal aorta
  • initially form mesonephric tubules (epithelial)
  • these tubules connect to a common duct, mesonephric duct
  • the mesonephric duct then extends within the mesoderm, rostro-caudally
  • eventually making contact with the cloaca

Mesonephric Duct

Later in development, both the mesonephric duct and the cloaca both continue to differentiate and undergo extensive remodelling (and renaming)

Uteric Bud

Mouse E12.5 kidney in vitro
  • arise near the cloacal connection of the mesonephric duct
  • branch from the mesonephric duct laterally into the intermediate mesoderm
  • induce the surrounding mesoderm to differentiate - metanephric blastema
    • this mesoderm will in turn signal back to differentiate the uteric bud

Epithelial - mesenchymal interaction

Uteric Bud forms - ureter, pelvis, calyces, collecting ducts

Metanephric Blastema

  • forms glomeruli, capsule, nephron tubules
  • this development continues through fetal period

Nephros Development

Three pairs appearing in sequence within intermediate mesoderm during development.

  1. pronephros
  2. mesonephros
  3. metanephros

Pronephros

  • week 4 few cells in cervical region fish
  • Human E18, Mouse E7.5pronephric duct forms first with associated nephrogenic mesenchyme
  • grows rostro caudally cervical -> cloaca
  • E22 nephrogenic mesenchyme differentiates to form pronephroi not functional in mammals degenerates rapidly

Mesonephros

Stage 13 mesonephros
Stage 22 mesonephros
  • Human E24, Mouse E9.5 caudal to pronephros
  • forms by induction from pronephros
  • pronephric duct now becomes mesonephric duct (also called Wolffian Duct)

Metanephros

  • Human E35-37, Mouse E11 epithelia bud at end of mesonephric duct uteric bud and associated metanephric mesenchyme

Uteric Bud

  • induced by metanephric mesenchyme to differentiate
  • forms collecting tubules, renal pelvis, ureter
  • metanephric mesenchyme induced by uteric to differentiate forms nephron

Nephron

Adult nephron structure
Nephron histology

In humans, nephrogenesis only occurs before birth, though nephron maturation continues postnatally. Mean glomerular number shown to level at 36 weeks, increasing from about 15,000 at 15 weeks to 740,000 at 40 weeks.

Nephron development has four identifiable developmental stages:
  1. Vesicle (V) stage (13-19 weeks, second trimester)
  2. S-shaped body (S) stage ( 20-24 weeks, second trimester)
  3. Capillary loop (C) stage (25-29 weeks, third trimester)
  4. Maturation (M) stage (infants aged 1-6 months, neonatal and postnatal)
Renal 001 icon.jpg
 ‎‎Nephron
Page | Play

Nephron Development

  • disorganised mesenchymal cells become a highly organised epithelial tubule
  • Condensation - groups of about 100 cells condense tightly together to form a distinct mass
  • Epithelialisation - condensed cells lose their mesenchymal character and gain epithelial
  • At end of this period formed a small epithelial cyst complete with a basement membrane, cell-cell junctions and a defined cellular apico-basal polarity.

Early morphogenesis

  • cyst invaginates twice to form a comma
  • then a S-shaped body one invagination site later becomes the glomerular cleft
  • At about this time blood vessel progenitors invade cleft to begin construction of vascular component of glomerulus
  • Tubule maturation specialised transporting segments of nephron differentiate complex of convoluted tubules is created

Endocrine Kidney

Covered also in Endocrine Development lecture

  • Renin - Increase Angiotensin-aldosterone system
  • Prostaglandins - decrease Na+ reabsorption
  • Erythropoietin - Increase Erythrocyte (rbc) production
  • 1,25 (OH)2 vitamin D - Calcium homeostasis
  • Prekallikreins - (plasma protein inactive precursor of kallikrein) Increase kinin production (altered vascular permeability)

Cloaca

File:Endoderm development

  • hindgut region ending at the cloacal membrane
  • divided (ventro-dorsally) by the urogenital septum
    • ventral - common urogenital sinus
    • dorsal - rectum
Urogenital septum 001 icon.jpg
 ‎‎Urogenital Septum
Page | Play

Common urogenital sinus

  • superior end continuous with allantois
  • common urogenital sinus and mesonephric duct fuse (connect)
  • differentiates to form the bladder
  • inferior end forms urethra
    • this will be different in male and female development

Urinary Bladder

Adult bladder
Trigone 001 icon.jpg
 ‎‎Trigone
Page | Play
  • early origins of the bladder at the superior end of the common urogenital sinus
  • 8 open inferiorly to the cloaca and superiorly to the allantois
  • Septation of the claoca - divides the anterior region to the primordial bladder component from the posterior rectal component.
  • associated ureters and urethra

Dorsal view of developing bladder

  • Ultrasound measurement of the bladder size can be used as a diagnostic tool for developmental abnormalities.

Bladder Structure

Bladder histology

Can be described anatomically by its 4 layers from outside inward:

  • Serous - the superior or abdominal surfaces and the lateral" surfaces of the bladder are covered by visceral peritoneum, the serous membrane (serosa) of the abdominal cavity, consisting of mesthelium and elastic fibrous connective tissue.
  • Muscular - the detrusor muscle is the muscle of the urinary bladder wall.
  • Submucosa - connects the muscular layer with the mucous layer.
  • Mucosa - (mucus layer) a transitional epithelium layer formed into folds (rugae).

Detrusor Muscle

  • The adult detrusor muscle consists of three layers of smooth (involuntary) muscle fibres.
    • external layer - fibres arranged longitudinally
    • middle layer - fibres arranged circularly
    • internal layer - fibres arranged longitudinally

Ureter Development

  • The adult ureter is a thick-walled muscular tube, 25 - 30 cm in length, running from the kidney to the urinary bladder.
  • Anatomically can be described in two parts the abdominal part (pars abdominalis) and pelvic part (pars pelvina).
  • The ureter is composed of three layers: outer fibrous layer (tunica adventitia), muscular layer (tunica muscularis) and mucous layer (tunica mucosa).
  • The muscular layer can also be subdivided into 3 fibre layers: an external longitudinal, a middle circular, and an internal longitudinal.

Trigone Development

Trigone 001 icon.jpg
 ‎‎Trigone
Page | Play

Kidney Ascent

early fetal kidney
Renal blood 01 icon.jpg
 ‎‎Renal Vascular
Page | Play
  • Pro-, Meso-, Meta- Early development descending
  • Metanephros - initially pelvic, beside aorta
  • Growth and straightening of body - Kidneys in abdomen and displace laterally

Renal Arteries

  • Arise with ascent and inferior branches lost
  • Sequential, 25% population have 2 or more renal arteries
  • branch of abdominal aorta, divides into 4-5 branches
    • each gives off small branches to suprarenal glands, ureter, surrounding cellular tissue and muscles

Note: Frequently a second renal artery (inferior renal) from abdominal aorta at a lower level, supplies lower portion of kidney

Abnormalities

Australian renal abnormalities

There are many different forms of renal development abnormalities associated with kidney, ureters, bladder and urethra. There are many genetic disorders associated with failure or abnormal renal development. Prenatal diagnosis of obstructive and renal agenesis/dysgenesis disorders are also important for early reproductive decisions by the parents. For example, with bilateral renal agenesis, failure of both kidneys to development, is not compatible with fetal/neonatal survival. Because of their close developmental association, often described as the urogenital system, there can be an associated genital abnormalities.


More detailed information is available on the links below.


Links: Renal Abnormalities | Genital Abnormalities

Horseshoe Kidney

Horseshoe kidney
  • fusion of the lower poles of the kidney.
  • During migration from the sacral region the two metanephric blastemas can come into contact, mainly at the lower pole.
  • The ureters pass in front of the zone of fusion of the kidneys.
  • The kidneys and ureters usually function adequately but there is an increased incidence of upper urinary tract obstruction or infection.
  • Some horseshoe variations have been described as having associated ureter abnormalities including duplications.

Urorectal Septum Malformation

  • thought to be a deficiency in caudal mesoderm which in turn leads to the malformation of the urorectal septum and other structures in the pelvic region.
  • Recent research has also identified the potential presence of a persistent urachus prior to septation of the cloaca (common urogenital sinus).

Bladder

  • absent or small bladder - associated with renal agenesis.

Bladder Exstrophy

Bladder_Exstrophy
  • developmental abnormality associated with bladder development.
  • origins appear to occur not just by abnormal bladder development, but by a congenital malformation of the ventral wall of abdomen (between umbilicus and pubic symphysis).
  • There may also be other anomolies associated with failure of closure of abdominal wall and bladder (epispadias, pubic bone anomolies).

Ureter and Urethra

  • Ureter - Duplex Ureter
  • Urethra- Urethral Obstruction and Hypospadias


Polycystic Kidney Disease

Multicystic kidney
  • diffuse cystic malformation of both kidneys
  • cystic malformations of liver and lung often associated, Often familial disposition
  • Two types
    • Infantile (inconsistent with prolonged survival)
    • Adult (less severe and allows survival)
  • Autosomal dominant PKD disease - recently identified at mutations in 2 different human genes encoding membrane proteins (possibly channels)

Wilms' Tumor

  • (nephroblastoma) Named after Max Wilms, a German doctor who wrote first medical articles 1899
  • most common type of kidney cancer children
  • WT1 gene - encodes a zinc finger protein
  • Both constitutional and somatic mutations disrupting the DNA-binding domain of WT1 result in a potentially dominant-negative phenotype
  • some blastema cells (mass of undifferentiated cells) persist to form a ‘nephrogenic rest’
  • Most rests become dormant or regress but others proliferate to form hyperplastic rests
  • any type of rest can then undergo a genetic or epigenetic change to become a neoplastic rest
  • can proliferate further to produce a benign lesion (adenomatous rest) or a malignant Wilms’ tumour


Prune Belly Syndrome

  • lower urinary tract obstruction
  • mainly male
  • fetal urinary system ruptures leading to collapse and "prune belly" appearance.

Renal Cysts

The Bosniak classification system (Category I - IV) was designed to separate identified cystic renal masses by analysis of computed tomography (CT) features into surgical and nonsurgical categories.[7] Named after Morton Bosniak, Yale University School of Medicine, the developer of this classification system.

Molecular

  • Foxd1 - (Brain Factor-2) transcription factor that is a renal stroma specific gene.


Links: OMIM Foxd1

References

  1. J R Nyengaard, T F Bendtsen Glomerular number and size in relation to age, kidney weight, and body surface in normal man. Anat. Rec.: 1992, 232(2);194-201 PMID:1546799
  2. M F Schreuder, J Nauta Prenatal programming of nephron number and blood pressure. Kidney Int.: 2007, 72(3);265-8 PMID:17495859
  3. Kun Xu, Xinyu Wu, Ellen Shapiro, Honging Huang, Lixia Zhang, Duane Hickling, Yan Deng, Peng Lee, Juan Li, Herbert Lepor, Irina Grishina Bmp7 functions via a polarity mechanism to promote cloacal septation. PLoS ONE: 2012, 7(1);e29372 PMID:22253716
  4. Kun Xu, Xinyu Wu, Ellen Shapiro, Honging Huang, Lixia Zhang, Duane Hickling, Yan Deng, Peng Lee, Juan Li, Herbert Lepor, Irina Grishina Bmp7 functions via a polarity mechanism to promote cloacal septation. PLoS ONE: 2012, 7(1);e29372 PMID:22253716
  5. Osman Sulak, Gülnur Ozgüner, Mehmet Ali Malas Size and location of the kidneys during the fetal period. Surg Radiol Anat: 2011, 33(5);381-8 PMID:21110022
  6. Weibin Zhou, Rudrick C Boucher, Frank Bollig, Christoph Englert, Friedhelm Hildebrandt Characterization of mesonephric development and regeneration using transgenic zebrafish. Am. J. Physiol. Renal Physiol.: 2010, 299(5);F1040-7 PMID:20810610
  7. Gary M Israel, Morton A Bosniak How I do it: evaluating renal masses. Radiology: 2005, 236(2);441-50 PMID:16040900 | Radiology

Textbooks

  • The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Moore and T.V.N Persaud - Moore & Persaud Chapter 13 p303-346
  • Larsen’s Human Embryology by GC. Schoenwolf, SB. Bleyl, PR. Brauer and PH. Francis-West - Chapter 10 p261-306
  • Before We Are Born (5th ed.) Moore and Persaud Chapter14 p289-326
  • Essentials of Human Embryology, Larson Chapter 10 p173-205
  • Human Embryology, Fitzgerald and Fitzgerald Chapter 21-22 p134-152

Online Textbooks

Search Bookshelf intermediate mesoderm | kidney development | renal development | ureteric bud | nephron development | bladder development

Reviews

Melissa Little, Kylie Georgas, David Pennisi, Lorine Wilkinson Kidney development: two tales of tubulogenesis. Curr. Top. Dev. Biol.: 2010, 90();193-229 PMID:20691850

Gregory R Dressler Advances in early kidney specification, development and patterning. Development: 2009, 136(23);3863-74 PMID:19906853

Odyssé Michos Kidney development: from ureteric bud formation to branching morphogenesis. Curr. Opin. Genet. Dev.: 2009, 19(5);484-90 PMID:19828308

Kimberly J Reidy, Norman D Rosenblum Cell and molecular biology of kidney development. Semin. Nephrol.: 2009, 29(4);321-37 PMID:19615554

Susan E Quaggin, Jordan A Kreidberg Development of the renal glomerulus: good neighbors and good fences. Development: 2008, 135(4);609-20 PMID:18184729

Andrea Brenner-Anantharam, Cristina Cebrian, Richard Guillaume, Romulo Hurtado, Tung-Tien Sun, Doris Herzlinger Tailbud-derived mesenchyme promotes urinary tract segmentation via BMP4 signaling. Development: 2007, 134(10);1967-75 PMID:17442697

Forefronts Symposium on Nephrogenetics: from development to physiology March 8-11, 2007 Danvers, MA A meeting to synthesize an integrated view of the normal development and function of the kidney from the genetic standpoint.

Frank Costantini Renal branching morphogenesis: concepts, questions, and recent advances. Differentiation: 2006, 74(7);402-21 PMID:16916378


Articles

Malin M Rhodin, Brian J Anderson, A Michael Peters, Malcolm G Coulthard, Barry Wilkins, Michael Cole, Etienne Chatelut, Anders Grubb, Gareth J Veal, Michael J Keir, Nick H G Holford Human renal function maturation: a quantitative description using weight and postmenstrual age. Pediatr. Nephrol.: 2009, 24(1);67-76 PMID:18846389


Search PubMed

Search April 2010

  • Renal System Development - All (4837) Review (1505) Free Full Text (1079)
  • Renal Development - All (31984) Review (7014) Free Full Text (6564)

Search Pubmed: Renal System Development | Renal Development | intermediate mesoderm | kidney development | renal development | ureteric bud | nephron development | bladder development

Additional Images

Terms

bladder exstrophy - A congenital malformation with bladder open to ventral wall of abdomen (between umbilicus and pubic symphysis) and may have other anomolies associated with failure of closure of abdominal wall and bladder (epispadias, pubic bone anomolies).

blastema - Term used to describe a mass of undifferentiated cells. (More? Wilm's tumour)

diabetes insipidus - The disorder is related to the hormone antidiuretic hormone (ADH, also called vasopressin) its synthesis, secretion, receptors and signaling pathway. In diabetes insipidus there is an excretion of large amounts (up to 30 litres/day) of a watery urine and an unremitting thirst.

hydronephrosis - (congenital hydronephrosis, Greek, hydro = water) A kidney abnormality due to partial or complete obstruction at the pelvi-ureteric junction. This leads to a grossly dilated renal pelvis causing extensive renal damage before birth.

hyperplastic rests - In kidney development, embryonic blastema cells can persist and proliferate to form a pool of cells, which under either genetic or epigenetic influence can then change to become a neoplastic rest. Normally the majority of nephrogenic rests either regress or become dormant.

mesonephros - The second temporary stage of kidney development (pro-, meso-, meta-). The intermediate mesonephros develops and disappears with the exception of its duct, the mesonephric duct, which will form the male reproductive duct system. In males, the mesonephric tubules go on to form the ducts of the testis. In females, these degenerate. A few mesonephric tubules remain as efferent ductules in the male and vestigial remnants in the female.

mesonephric duct - (= Wollfian duct) An early developing urogenital duct running the length of the embryo that will differentiate and form the male reproductive duct system. In females this duct degenerates (some remnants may remain associated in broad ligament).

metanephros - The adult kidney, third stage of mammalian kidney (pro-, meso-, meta-) development within the intermediate mesoderm.

metanephric cap - In kidney development, the intermediate mesoderm which surrounds the ureteric bud and will develop into nephrons.

Multicystic Kidney - There is no functional kidney tissue present in the kidney and it is replaced by a multilocular cyst. This is non-familial and is produced by atresia of a ureter and is always unilateral.

neoplastic rest - In kidney development, a neoplastic rest can develop under either genetic or epigenetic influence from a hyperplastic rest, originating from an embryonic blastema cell. Normally the majority of nephrogenic rests either regress or become dormant.

nephrogenic rest - A kidney term used to describe the embryonic blastema cells which persist and under either genetic or epigenetic can change to become a neoplastic rest. These neoplastic rests can develop postnatally as a benign form (adenomatous rest) or a malignant Wilm's tumour form. The rests are further characterised by the time of generation leading to different anatomical kidney locations: early intralobar nephrogenic rests (within the renal lobe) and late pelilobar nephrogenic rests (periphery of the renal lobe) nephron - (Greek, nephros = kidney) The functional unit of the kidney.

nephros - (Greek, nephros = kidney) Term used to describe features associated with the kidney. (pronephros, mesonephros, metanephros, nephric, nephron, nephroblastoma).

podocyte - (visceral epithelial cell) kidney glomerulus cell forming the main component of the glomerular filtration barrier.

podocyte specific proteins - podocalyxin, glomerular epithelial protein-1, podocin, nephrin, synaptopodin, and alpha-actinin-4), podocyte synthesized proteins (vascular endothelial growth factor and novH), transcription factors (WT1 and PAX2).

pronephros - (Greek, pro = before) The first temporary stage of kidney development (pro-, meso-, meta-). This forms the kidney of primitive fish and lower vertebrates. Kidney development occurs within the intermediate mesoderm interacting with endoderm. In humans, this very rudimentary kidney forms very early at the level of the neck. It is rapidly replaced by the mesonephros, intermediate stage kidney, differentiating in mesoderm beneath.

proteinuria - The abnormal presence of protein in the urine and an indicator of diesease including diabetic kidney disease (DKD, diabetic nephropathy).

renal - (Latin, renes = kidney) Term used in relation to the kidney and associated structures (renal pelvis, renal artery)

ureter - The two ureters are hollow tubes that link and carries urine from kidney to the bladder. The tubes have a muscular wall lined with transitional epithelium.

urethra - The single muscular tube that links and carries urine from the bladder to the exterior. In humans, the urethral length differs between the sexes (male longer, female shorter).

urinary - Term used to describe all components of the kidney system including the bladder, ureters and urethra.

urine - Term used to describe the liquid waste produced by the kidney, stored in the bladder and excreted from teh body through the urethra.

urorectal septum - (URS) The structure which develops to separate the cloaca (common urogenital sinus) into an anterior urinary part and a posterior rectal part.

Wilms' tumour - A form of kidney/renal cancer (nephroblastoma) named after Dr Max Wilms who first described the tumor. This childhood kidney cancer is caused by the inactivation of a tumour suppressor gene (BRCA2) or Wilms tumor-1 gene (Wt1) and is one of the most common solid tumors of childhood, occurring in 1 in 10,000 children and accounting for 8% of childhood cancers. Wt1 also required at early stages of gonadal development. (More? OMIM - Wilm's tumour | Dr Max Wilms)

Wilms' tumor 1-associating protein - (WTAP) protein expressed in extraembryonic tissues and required for the formation of embryonic mesoderm and endoderm.

Wolffian duct - (= mesonephric duct, preferred terminology), runs from the mesonephros to cloaca, differentiates to form the male vas deferens and in the female regresses. Named after Caspar Friedrich Wolff (1733-1794), a German scientist and early embryology researcher and is said to have established the doctrine of germ layers. (More? Caspar Friedrich Wolff)

External Links

External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name.



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Cite this page: Hill, M.A. (2014) Embryology Renal System Development. Retrieved April 16, 2014, from http://embryology.med.unsw.edu.au/embryology/index.php?title=Renal_System_Development

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Dr Mark Hill 2014, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
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