Lecture 4- Embryology Flashcards
What does the urogenital system arise from?
Intermediate mesoderm
What does the intermediate mesoderm form?
Urogenital ridge
What does the urogenital ridge develop into?
Pronephros
Mesonephros
Metanephros
Pronephros
Most cranial set of tubes
Regresses
Mesonephros
Located along the midsection of the embryo
Develops into the mesonephric tubules and mesonephric ducts
Mesonephric tubules
Have some crude kidney function at first, but then mostly regresses
Mesonephric duct
Persists and opens to the cloaca at the tail of the embryo
Metanephros
Most caudal part of urogenital ridge
Forms adult kidney
Develops from the ureteric bud (outgrowth of caudal mesonephric duct) and the metanephric blastema (renogenic intermediate mesoderm)
Nephrogenic cord
Cleaves into nephrotomes
Nephrotomes hollows out into nephrotomal vesicle, which become oval and then S-shaped
The vesicles then fuse, which forms the pronephric duct
What does the ureteric bud give rise to
“Collecting system”
Ureter, renal pelvis, calyces, papillary ducts, and collecting ducts
Goes through consecutive rounds of bifurcation, elongation, and fusion
Metanephric blastema
Gets compressed by the ureteric bud and undergoes the same transformations described for nephrotomes
Gives rise to the nephrons or “excretory system”
Urine formation
Urine is actively formed during prenatal life, but isn’t required
After birth, no more functional units (nephrons) are formed
Describe changes in the position of the kidney
Metanephros is initially located in the pelvic region, but shifts to a more cranial position- “ascent” of the kidney
Hilum initially faces ventrally, but ends up facing medially
How are the urogenital sinnus and anorectal canal formed?
During the separation of the endodermal cloaca by the urorectal septum
Renal agenesis
One or both kidneys fail to develop
Ectopic kidney
When a kidney develops in a place it shouldnt
Horseshoe kidney
Two developing kidneys fuse into a single, horseshoe-shaped kidney
Congential cystic kidney disease
Common in persian cats
Cysts develop in the kidney tissue
Where do the gonads arise from
Intermediate mesoderm
Where do the genital ducts arise from
Mesonephric (wolffian) and paramesonephric (mullerian)
Describe development of male repro tract
Gonads develop into testis under SRY gene
Testis produce testosterone, which fosters growth of mesonephric ducts
Testosterone is also converted to DHT, which supports development to of penis, scrotum, and prostate
Sertoli cells produce anti-mullerian hormone
What does genital tubercle become
Male- body and glans of penis, erectile tissue
Female- body and glans of clitoris
What does genital fold turn into
Male- ventral aspect of penis and penile raphe
Female- labia minora
Genital swellings turn into?
Male- scrotum and scrotal raphe
Female- labia major
