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CVPR: Renal > Development of the Kidney > Flashcards

Flashcards in Development of the Kidney Deck (11)
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1

"3 sets of kidneys" + destiny

  1. pronephros (3-4wks) ==> degenerate
  2. mesonephros (4wks-2mos) ==> male reproductive ductwork
    1. First two stages help 3rd develop
  3. metanephros (5wks-maturity) ==> definitive adult kidney

2

Early development of "3 sets of kidneys"

  • all structures develop from nephrogenic cord @ urogenital ridge
    • urogenital ridge = tissue runs lateral and ventral to dorsal aorta along coelom of embryo
  • mesodermal cells @ nephrogenic cord ==> groups called nephrotomes
  • nephrotomes vesiculate + join ==> eventually becomes mesonephric duct

3

Characteristiscs of mesonephric duct/destiny of duct

  • formed by fusion of nephrotomes w/in nephrogenic cord
  • grows caudally to join developing cloaca
  • remaining portion = "wolffian duct"
  • males ==> epididymus and ductus deferens
  • females ==> mostly degenerate

4

Characteristics of urogenital ridge

  • tissue that runs laterally and ventrally to the dorsal aorta lengthwise along the coelom of the embryo
  • ==> wolffian body => protrudes further into coelom

5

Characteristics of paramesonephric duct

  • aka "Mullerian duct"
  • develops along urogenital ridge
  • runs along length of Wolffian body; joins w/cloaca
  • males => degenerates
  • females => forms oviduct and uterus

6

Major aspects of development of metanephros

  • ureteric bud
  • collecting ducts and tubules
  • glomeruli/nephron development

7

Development of the ureteric bud

  • =small bud of epithelial cells @ mesonephric duct
  • eveloped by region of cells = metanephric blastema
  • ureteric bud => lengthwise growth + branching => ureter + renal pelvis + major/minor calcyces

8

Development of collecting ducts and tubules

  • epithelia from ureteric bud ==> outgrowth tubules ==> parallel, aligned tubules = Malpighian pyramids
  • these eventually become collecting ducts + collecting tubules

9

Development of glomeruli/nephrons

  • mesoderm @ metanephric blastema ==> metanephric spheroid @ tips of collecting tubules ==> metanephric vesicle
  • vesicle elongates => tubule => S-floding => metanephric tubule ==> rest of nephron
    • fuses w/collecting tubules
    • forms envelop around glomerular capillaries = Bowman's capsule
    • differetiates into different regions of nephron (PT, LOH, DCT)

10

Development of the bladder/urethra

  • urogenital sinus = originates as endoderm from cloaca
    • separates from hindgut @ 6-7wks
    • allantois degenerates => urachus (fibrous cord)
    • bladder and urethra form
  • males
    • uteretic duct connects w/bladder
    • mesonephric duct separates and rejoins @ eventually connects w/urethra

11

Kidney positioning during development

  • as ureteric bud elongates => kidney ascends from sacral region => retroperitoneal location
  • males: testes connected to wolffian duct descend