Embryology Flashcards
What germ layer gives rise to the urogenital systems?
Intermediate mesoderm gives rise to urogenital ridge
What are the two divisions of the urogenital ridge?
Nephrogenic cord
Genital ridge
What are the three sets of kidneys that develop in a cascade?
Pronephros
Mesonephros
Metanephros
When does the pronephros develop and then subsequently degrade?
Develops in the beginning of wk 4 and is degraded by the end of it
What is the time frame of the mesonephros?
Wks 4-8
What develops from the cervical and upper thoracic part of the nephrogenic cord?
Pronephros
What part of the pronephros persists and what does it become?
Pronephric duct grows caudally and becomes mesonephric duct
What is another name of the mesonephric duct?
Wolffian duct
What develops from the lower thoracic and upper lumbar part of the nephrogenic cord?
Mesonephric kidney
What are the parts of the mesonephric kidney?
70-80 mesonephric tubules
Mesonephric duct
Glomerulus
What is the fate of the mesonephric tubules?
Males –> efferent ductules of testis
Females - epoophoron and paroophoron in broad ligament of uterus
What is the fate of the mesonephric duct?
Males: collecting system of kidney, vas deferens, ejaculatory duct, seminal gland
Females: collecting system of kidney, gartner duct
When does the metanephros begin to develop?
Wk 5
What develops from the lumbosacral part of the nephrogenic tube?
Metanephros
What are the two main parts of the metanephros?
Metanephric blastema
Ureteric bud
What develops from the metanephric blastema?
Excretory parts
Bowman’s capsule
PCT
Loop of Henle
DCT
What develops from the ureteric bud?
Collecting parts
Collecting duct
Minor and major calyces
Renal pelvis
Ureter
How does the collecting part develop?
Subsequent branching from renal pelvis
How does the collecting part develop?
Subsequent branching from renal pelvis
First branches - major calyces
2nd-4th branches - minor calyces
5th+ - collecting tubules
What are the precursors of nephrons?
Renal vesicls
When does tubular function in the metanephros begin?
Week 10
When does reabsorption of filtrate begin in the loop of Henle begin?
Wk 13
What mainly contributes to the increase in kidney size after birth?
Elongation of PCT
Increase interstitial tissue
What is the branching of the ureteric bud dependent on?
Induction by the metanephric mesenchyme
What does differentiation of the nephrons depend on?
Induction by the collecting tubules
What is needed for reciprocal induction?
WT1 - transcription factor
Makes the metanephric mesoderm competent to respond
What contributes to the ascent of the kidneys?
Diminution of the fetal curvature
Growth of body wall caudal to developing kidney
When do kidneys reach their adult position?
Wk 9
What is the normal rotation of the kidneys during development?
Hilum starts of ventrally
Kidneys rotate medially as they ascend
Hilum then faces anteromedially
What causes Potter sequence?
Prolonged period of oligohydramnios causing fetal compression
What are the physical abnormalities associated with Potter sequence?
Flattened nose
Low-set ears
Recessed chin
Limb deformities
What causes multicystic dysplastic kidney?
Ureteric bud does not develop so their is fluid buildup in the kidneys leading to numerous renal cysts
Non-inheritable genetic abnormality
What prevents the normal ascent in horseshoe kidney?
Inferior mesenteric A
What is a complication of accessory renal A?
Can obstruct ureter
What results in duplications of abdominal part of ureter and renal pelvis?
Abnormal division of the ureteric bud
What is an ectopic ureter?
Duplicated ureter that does not join distally and instead enters the bladder in a separate location
What are the divisions of cloaca?
Urogenital sinus
Primitive rectum
What divides the cloaca?
Urorectal septum
What are the divisions of the urogenital sinus?
Vesicourethral canal
Definitive urogenital sinus
What germ layer gives rise to the mucosa of the bladder?
Endoderm
What develops into the mucosa of the trigone within the bladder?
Absorption of the mesonephric ducts - mesoderm
What gives rise to the musculature of the bladder?
Splanchnopleuric layer of lateral plate mesoderm
What are the 3 parts of the male urethra?
Prostatic part
Membranous part
Spongy part
What gives rise to the prostatic urethra above the ejaculatory duct?
Ventral wall from endoderm of vesicourethral canal
Dorsal wall from mesonephric ducts - mesoderm
What gives rise to the prostatic urethra below the ejaculatory duct?
Endoderm of the pelvic part of the urogenital sinus
What gives rise to the membranous urethra?
Endoderm of pelvic segment of urogenital sinus
What gives rise to the spongy urethra?
Endoderm of phallic segment of urogenital sinus
What gives rise to the small part of the urethra within the glans penis?
Ectodermal groove
What gives rise to the entire urethra in females?
From the vesico-urethral part of endodermal cloaca
What can cause posterior urethral valve?
Oligohydramnios
Erroneous integration of mesonephric ducts
What are signs of a posterior urethral valve?
Hydronephrosis
Hypertrophy of bladder
Vesicoureteral reflux
Infections
