Urinary Bladder Development
Introduction
The paired adult kidneys filter blood, reabsorb water, have endocrine functions and excrete waste. The waste in the form of urine for excretion, collects initially in the renal pelvis and flows through the ureters to the urinary bladder. The common name for the urinary bladder is simply "bladder".
Some Recent Findings
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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
Movies
Urogenital Sinus | Urogenital Septum | Trigone | Urogenital | Renal Nephron |
Cloaca
- hindgut region ending at the cloacal membrane
- divided (ventro-dorsally) by the urogenital septum
- ventral - common urogenital sinus
- dorsal - rectum
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
- 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
Trigone formation animation | small animation
- Ultrasound measurement of the bladder size can be used as a diagnostic tool for developmental abnormalities.
Bladder Structure
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
Embryonic Urinary Bladder
The Carnegie stage 22 human male embryo is 27mm (CRL) in size and approximately equal to day 54 - 56 of development. These images have been selected to show some key features of late embryo development.
G5 urogenital | G6 urogenital | G7 urogenital |
Fetal Urinary Bladder
Fetal Development - 10 Weeks - Early female fetal bladder development. Anatomically lying behind the pubic symphysis and in front of the developing uterus. Surrounded by the developing detrusor muscle and the superior end extending towards the ventral body wall herniation.
midline section | medial section |
- Links: Fetal Development - 10 Weeks
Newborn Urinary Bladder
The Newborn Male Bladder | The Newborn Female Bladder |
Abnormalities
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
- 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
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.
Images
References
- ↑ <pubmed>19914648</pubmed>PMC2794964 | J Urol.
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
- Developmental Biology by Gilbert, Scott F. Sunderland (MA): Sinauer Associates, Inc.; c2000 Chapter 14 Intermediate Mesoderm | Figure 14.18. General scheme of development in the vertebrate kidney | Figure 23-23. Mechanism of mesenchymal inductive effect on the ureteric bud | Figure 14.21. Ureteric bud growth is dependent on GDNF and its receptor
- Molecular Cell Biology by Lodish, Harvey; Berk, Arnold; Zipursky, S. Lawrence; Matsudaira, Paul; Baltimore, David; Darnell, James E. New York: W. H. Freeman & Co.; c1999 Reciprocal Epithelial-Mesenchymal Interactions Regulate Kidney Development | Figure 23-21. Embryonic development of the kidney
Reviews
<pubmed>19461520</pubmed> <pubmed>17442697</pubmed> <pubmed>16916378</pubmed>
Search Bookshelf intermediate mesoderm | bladder development
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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).
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.
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).
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.
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)
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Cite this page: Hill, M.A. (2024, May 21) Embryology Urinary Bladder Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Urinary_Bladder_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G