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Urogenital system
- Intermediate mesoderm
- -urogenital ridge
- --gonadal ridge
- --nephrogenic cord-nephron: produce the urine, ducts: collecting system (collect urine an dtake to bladder)
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three separate kidneys develop
- pronephros-neck
- mesonephros
- metanephros-beomes adult kidney
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Pronephros
- appears in 4th week and then degenerates
- -Pronephric ducts
- -Pronephric tubule-never form urine
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mesonephros
- appears late in 4th week, functional until 11 weeks
- males-becomes reproductive system
- -mesonephric ducts-was pronephric duct-renamed
- -mesonephric tubule-produce urine
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metanephros
- begin to develop in 5th week, functional and definitive
- -ureteric bud-outgrowth from mesonephric duct
- -metanephrogenic blastema (or mass)-intermediate mesoderm surrounds uteric bud
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induction on nephrons
- mesonephric duct-induces nephrons in adjacent nephrogenic cord-get vesicle formed
- -blood supply forms in the glomerulus
- -collecting system forms to connect to the mesonephric duct
- -mesonephric excertion-urine
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nephron
- functional unit of kidney
- -glomeruli (capillaries)-lateral plate
- -Bowman's capsule-IM
- -Mesonephric tubule-IM
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development of true kidney
- metanephros
- -uteric bud (metanephric duct): out growht from mesonephric duct
- -metanephric blastema: derived from the nephrogenic cord
- ureteric bud (collecting system)-ureter, pelvis, major calyces, minor calyces, collecting tubules
- metanephric blastema (urine formation)-renal vesicles (lat plate), Bowman's capsule, Proximal and distal convoluted tubules, Loop of Henle
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development of the collecting system
- ureteric bud first contacts metanephric blastema and will give rise to renal pelvis
- ureteric bud bifurcates and branches coalesce (grow back together) to form major calyces
- branches will branch again and then coalesce to form the minor calyces
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development of the nephron
- nephron originates as a vesicle within the blastemic cap surrounding the ampulla of a collecting duct
- vesicle elongates into a tube and glomerulus forms at one end
- tubule near the glomerulus will invaginate and form Bowman's capsule
- the other end of the tubule lengthens and differentiates into the proximal convoluted tubule, Loop of Henle, and the distal convoluted tubule
- 1) duct induces nephron
- 2) tubule and duct system meet
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Renal blood supply and ascent of kidneys
- adult position by 9th week
- ascent results from caudal growth of embryo
- kidneys rotate 90 degrees during ascent
- receive blood supply from vessels that are closest to them
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kidney abnormalities
- pelvic kidney-stay down (pancake)-functional-no problems
- horseshow kidney-poles fuse-can start to ascend but can't because of IMA at L5
- Accessory renal vessels-due to ascent of kidney
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ureter and bladder
- ureter derived from mesonephric duct and metanephric duct
- bladder is hindgut endoderm
- trigone is mesoderm
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bladder
- hindgut endoderm
- cloacal membrane-endoderm and ectoderm
- -urogenital membrane-endoderm and ectoderm
- -anal membrane
- Allantois to urachus (median fold) to median umbilical ligament
- urogenital sinus (endoderm)
- -vesicle part: bladder
- -pelvis part: urethra(f), prostatic urethra (m)
- -Phallic: lining of vaginal vestibule (f), spongy urethra (m)
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allantois: Abnormalities
- urachal fistula-urine leaks out umbilicus
- urachal cyst
- urachal sinus
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congenital abnormalities of the bladder
- exstrophy of the bladder (ectopic vesicae)
- -arises during body folding (4th week)
- -defective closure of ventral abdominal wall
- -exposure of mucosa of the posterior wall of bladder
- -trigone-mesoderm
- Epispadias
- -improper location of genital tubercles caudal to cloacal membrane-bladder leads out of penis
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suprarenal glands
- Medulla (N.C.)-chromaffin system-symp. ganglia displaces, preganglionic
- Capsule-touch connective tissue-mesonephric mesoderm (I.M.)
- Cortex
- -coelomic epithelium (somatic mesoderm)
- --fetal cortex: first cellular wave
- --adult cortex: second cellular wave
- -fetal cortex: pituitary ACTH, glucocorticoids, and dihydroepiandrosterone (estrogen precursor)
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