1.2.2 Embryology and Development of Kidney and Urinary Tract Flashcards
What are some potential malformations of the bladder and urethra?
Extrophy of the bladder - exposure and protrustion of the posterior wall of the bladder through the abdominal wall
Epispadias - Urethra opens on the dorsal surface of the penis
Hypospadias - Urethra opens on the ventral side of the penis
What is this an image of?
Wilms tumor - blastema
What is the origin of the metanephric kidney?
It forms from the metanephric blastema which forms from the intermediate mesoderm
The Ureteric bud comes from the mesonephric duct and penetrates the metanephric blastema.
Does the kidney ascend?
What is congenital virilizing hyperplasia?
This is and Adrenogenital syndrome that can cause female pseudohermaphroditism
What are three types of urachal malformation?
Urachal malformations: A. Urachal Fistula, B. Urachal Cyst, C. Urachal Sinus
Describe the relationship of the ureters and the mesonephric ducts during development.
Dorsal views of the bladder showing the relationship of the ureters and mesonephric ducts during development. Initially, the ureters are formed by an outgrowth of the mesonephric duct (A), but with time they assume a separate entrance into the urinary bladder (B⇒D). Note the trigone of the bladder formed by the incorporation of the mesonephric ducts (C,D).
Describe the development of the Metanephric Excretory Unit. (This is a picture of a slide)
Is kidney development complete at birth?
What cells form the medulla of the adrenal cortex?
Chromaffin cells
Describe the development of the Urethra.
What is this an image of and describe the process that is occuring.
Ureteric bud and induction of Vesicles in the metanephric blastema’
Nephron development in the metanephros (57 days): Ureteric bud has induced a change in the surrounding mesenchyme of the metanephric blastema to convert the mesenchyme to an epithelium and form the S-shaped nephric (renal) vesicle seen in what was metanephric blastema. Concomitant, with the change there is a conversion of intermediate filament protein markers and the production of laminin and type IV collagen instead of fibronectin and type I collagen. The arrow shows the junction of the collecting tubule and the nephron portion
What is Potter Sequence/Syndrome?
These features are secondary to prolonged oligohydramnios secondary to bilateral renal agenesis, or anomalies in which the kidneys are present but there is an obstructed urethra, prolonged rupture of membranes, or severe growth retardation.
What is the medulla derived from?
Neural crest cells
What are the important genes involved in Metanephros differentiation?
WT1 - The only one he talked about
GDNF, HGF, BMP7 and WNT4
What is this an image of?
Wilms tumor - pointing at tubules
What does the Cloaca divide into?
Division of the cloaca into the urogenital sinus and anorectal canal. The mesoneprhic duct is gradually absorbed into the wall of the urogenital sinus, and the ureters enter separately. A. At the end of the 5th week. B. 7 weeks. C. 8 weeks.
Describe the development of the bladder.
Also know:
Mesonephric ducts and attached ureteric buds are intercalated into the posterior wall of the bladder - Exstrophy
Initially, the bladder is continuous with the allantois which forms the urachus which is know in the adult as the median umbilical ligament
The bladder is an abdominal organ in infants
What is this an image of?
Wilms tumor - stromal component
What are these images of?
Hypoplasia of the lung due to oligohydramnios
What does the Urogenital sinus develope into?
A. Development of the urogenital sinus into the urinary bladder and definitive urogenital sinus. B. In the male, the definitive urogenital sinus develops into the penile urethra. The prostate gland develops from outgrowths of the urethra and the seminal vesicles are formed as outgrowths of the developing ductus deferens.
What is this an image of?
Formation of the metanephros and continuing inductions
What is this an image of?
Ureteric bud and metanephric blastema
Describe the dysregulation of the fetal adrenal gland in congenital virilizing hyperplasia (Adrenogenital syndrome)
Normal feedback control of the adrenal cortex is lost in adrenogenital syndrome (congenital virilizing hyperplasia). Most often the cause is a mutation in the C21 hydroxylase enzyme resulting in an inability to synthesize corticosteroids. ACTH and CRH become elevated and increase secretion of dehydroepiandrosterone from the fetal adrenal cortex leading to elevated hydroxyprogesterone (precursor to cortisol) levels. The elevated dehydroepiandrosterone levels lead to masculinization of the female genitalia.
Describe the relation of the gonad and the mesonephros.
A. Transverse section through the urogenital ridge in the lower thoracic region of a 5-week-old embryo showing formation of an excretory tubule of the mesonephric system. Note the appearance of Bowman’s capsule and the gonadal ridge. The mesonephros and the gonad are attached to the posterior abdominal wall by a broad urogenital mesentery. B. Relation of the gonad and the mesonephros. The mesoneprhic (Wolffian) duct runs along the lateral side of the mesonephros.
Describe the regulation of the adrenal gland
Normal feedback control of the adrenal cortex occurs from the anterior pituitary through the secretion of adrencorticotrophic hormone (ACTH) with oversight from a higher authority—the hypothalamus (CRH, corticotrophic releasing hormone. Increased secretion of cortisol feeds back on the anterior pituitary resulting in decreased ACTH secretion and decreased secretion of the releasing hormone from the hypothalamus.
The pronephric system starts as what?
Segmented intermediate mesoderm which will then become the vestigal pronephric system
What is the importance of urine production in the embryo?
Included in this list are:
Placenta is the primary waste disposal system for fetus
Kidneys are essential organs at birth
Oligohydramnios
Describe the ascent of the kidney.
A ⇒ C. Ascent of the Kidneys. Note the change in position between the mesonephric and metanephric systems. The mesonephric system degenerates almost entirely, and only a few remnants persist in close contact with the gonad. In both male and female embryos, the gonads descend from their original level to a much lower position.
