Lecture 10: Renal Embryology Flashcards
Kidneys and gonads are derived from what kind of mesoderm?
Intermediate mesoderm
What is the urogenital ridge?
Longitudinal band of mesoderm that forms on each side of dorsal aorta
What does the urogenital ridge give rise to?
Nephrogenic cord
What does the nephrogenic cord give rise to?
Pronephros
Mesonephros
Metanephros
Describe the pronephros.
Appears early in 4th week in cervical region
- ducts run caudally into cloaca
- degenerates pretty quickly but ducts remain
Describe the mesonephros.
Appears late in 4th week
- ducts develop early from pronephros ducts
- induce tubule from surrounding intermediate mesoderm
- produces urine
- has glomerulus and Bowman’s capsule
- degenerates by 12th week
In males, what does the mesonephros become?
Efferent ductules
Describe the metanephros.
Appears during 5th week and functional by 9th-10th week
- ureteric bud: from mesonephric duct and branches into sacral part of intermediate mesoderm
- metanephric blastema: from nephrogenic cord
What is the purpose of fetal kidneys?
Amniotic fluid production
How does the renal pelvis form?
Ureteric bud elongates and penetrates metanephric blastema
What gives rise to the ureter?
Stalk of ureteric bud
How do collecting tubules form?
Cranial part of ureteric bud continues to branch
-major and minor calyces
What do ureteric buds give rise to?
Ureter
Renal Pelvis
Major and minor calyces
Collecting ducts
What does the metanephric blastema give rise to?
Bowman’s Capsule
Proximal and Distal Convoluted Tubules
Loop of Henle
How do nephrons form?
1) Metanephric blastema can bud off and give rise to metanephric vesicles
2) Vesicles form metanephric tubules
3) Proximal end will form glomerular capsule
4) Tubule differentiates into PCT, DCT, and nephron loop
In what direction does the renal hilum rotate?
Medially by 90 deg
Where do renal arteries originally branch from?
Common Iliac Artery
What is renal agenesis?
Failure of development of kidney(s)
What is an incomplete division of the ureter?
Kidney has 2 ureters that eventually join later and make on single ureter
What is a complete division of the ureter?
Kidney has 2 ureters that do not join and remain separate until bladder
What is a horseshoe kidney?
Kidneys fused together at inferior poles
-low lying
What happens if there are extra renal vessels?
Multiple renal arteries that can potentially obstruct the ureter
What is multicystic dysplastic kidney disease?
Malformation of the kidney during fetal development
-irregular cysts of varying sizes from loop of henle
What is the difference between polycystic and multicystic kidney disease?
Polycystic: normally affects both kidneys
Multicystic: normally one kidney
What are the three parts of the urogenital sinus?
1) Vesical part: most of bladder
2) Pelvic part: neck of bladder
3) Phallic part: spongy urethra in males and lining of vaginal vestibule in females
How is trigone formed?
1) Mesonephric duct incorporated in posterior wall of bladder
2) Ureteric bud attaches, connecting openings of buds into bladder wall
3) Mesonephric duct opening carried inferiorly to pelvic urethra
*Trigone is blending of mesonephric and ureteric ducts
What type of mesoderm is found in trigone?
Intermediate mesoderm
What type of mesoderm is found in submucosa and muscles of bladder?
Splanchnic mesoderm
What is bladder continuous with?
Allantois –> urachus
How is medial umbilical ligament formed?
Urachus extends from apex of bladder to umbilicus forming ligament
What is exstrophy of the bladder?
Congenital abnormality: skin over the lower abdominal wall does not form properly
- posterior wall of bladder is open and exposed on the outside of abdomen
- defective closure of ventral abdominal wall
What is epispadias?
Urethral opening is on dorsum rather than ventral side of genital tubercle
What are urachal cysts?
Remnants of epithelial lining of urachus that can become infected and enlarged
What is an urachal sinus?
End of urachus remains open into bladder or umbilicus
What is an urachal fistula?
Entire urachus remains patent and allows urine to escape from umbilical orifice
From what cells are suprarenal glands derived from?
Neural Crest Cells
