Renal Embryology Flashcards

1
Q

Intermediate mesoderm separates from?

A

Lateral and paraxial mesoderm during folding

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2
Q

2 components that give rise to the urogenital system?

A

Nephrogenic cord and urogenital ridge

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3
Q

Nephrogenic cord leads to?

A

3 kidneys

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4
Q

Cervical nephrotomes (pronephros)

A
  • In the 4th week, 5-7 paired nephrotomes appear in cervical region
  • Their development is abortive
  • Remain nonfunctional until disappearance (day 24/25)
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5
Q

Mesonephros

A
  • During the 4th week, a second primitive kidney develops
  • Mesonephric tubules form within nephrogenic cords
  • About 40 tubules develop in craniocaudal succession
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6
Q

Mesonephric tubules

A
  • Very primitive nephrons
  • Regression of cranial tubules occurs with formation of distal ones
  • By 5th week, 20 pair of tubules are found in lumbar region
  • Differentiate into functional nephric units with glomeruli
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7
Q

Mesonephric ducts

A
  • Form at 24 days from cords dorsolateral to mesonephric tubules
  • Run caudally to empty into ventrolateral portion of cloaca
  • Fusion of tubule tip with duct provides passage from excretory unit–>cloaca
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8
Q

Mesonephros

  • When is it present and functional?
  • What happens after?
A
  • Present and functional from the 6th to the 10th weeks

- After week 10, it degenerates

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9
Q

Mesonephros

  • In the male?
  • In the female?
A
  • In the male, its duct system will contribute to part of the genital system
  • Also contributes to vestigial structures in the female
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10
Q

Summarize the normal epithelial-mesenchymal interactions that are involved in differentiation of the kidney (Figure 16.7 and clinical correlates 255-256)
-Metanephros: steps in renogenesis

A
  • Cranial-caudal patterning establishes a “renogenic” region within the intermediate mesoderm in the tail of the embryo
  • This renogenic mesoderm is the METANEPHRIC BLASTEMA
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11
Q

Describe the contributions of the ureteric bud and metanephric blastema or diverticulum to the metanephros (the definitive kidney)

A

The METANEPHRIC BLASTEMA secretes growth factors that induce growth of the URETERIC BUD from the caudal portion of the mesonephric duct

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12
Q

Metanephros: steps in renogenesis

-Ureteric bud secretes?

A

-URETERIC BUD secretes PAX2 and WNT4

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13
Q

Metanephros: steps in renogenesis

-PAX2-function?

A

PAX2 which promotes condensation of the mesenchyme preparatory to tubule formation

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14
Q

Metanephros: steps in renogenesis

-WNT4-function?

A

Causes the condensed mesenchyme to epithelialize and form tubules

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15
Q

Metanephros: steps in renogenesis

A

Modifications in the ECM also occur with change to laminin and type 4 collagen, characteristic of an epithelial basal lamina

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16
Q

Metanephros: steps in renogenesis

A

CAMs syndecan and E-cadherin are essential for condensation of the mesenchyme into an epithelium

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17
Q

In utero function of metanephros

  • When does blood plasma begin to be filtered?
  • Primary function?
A
  • Blood plasma from glomerular capillaries begins to be filtered by 10th week
  • Urine is produced, but the primary function is not to clear waste (placenta) but to supplement production of amniotic fluid
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18
Q

Oligohydramnios (insufficient amount of amniotic fluid) may indicate?

A

Bilateral renal agenesis or urethral obstruction

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19
Q

Describe the developmental changes in kidney position (figure 16.10)

A

?

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20
Q

How does ‘ascent’ of the kidneys explain accessory renal arteries and ectopic kidneys? (Clinical correlates 257-258)

A

Kidneys are formed in pelvis but ascend to lumbar region with progressive revascularization from common iliac and aorta-accessory renal arteries are common

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21
Q

Renal fusion

A
  • Prevents normal rotation
  • Abnormal blood supply-usually from middle sacral or common iliac arteries
  • Ectopic kidney-may also be crossed with/without fusion
  • Horseshoe kidney
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22
Q

Horseshoe kidney

A
  • Most common

- 90% fused at lower pole

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23
Q

Horseshoe kidney

-Usually found?

A

Usually found inferior to the inferior mesenteric artery

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24
Q

Describe the partitioning of the cloaca into the urogenital sinus and anal canal.(Figure 16.12)What changes, especially in the role of the mesonephric ducts, are made to the urogenital sinus to create the urinary bladder? (Figure 16.14)
-Cloaca is divided by the?

A

Urorectal septum

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25
Q

Development of the urinary bladder

  • The cloaca is divided by the urorectal septum
    - The dorsal (inferior) portion develops into?
A

The dorsal (inferior) portion develops into the rectum and anal canal

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26
Q

Development of the urinary bladder

  • The cloaca is divided by the urorectal septum
    - The ventral (superior) portion develops into?
A

The ventral superior portion develops into the bladder and urogenital sinus, which will give rise to the bladder and lower urogenital tracts (prostatic and penile urethrae in males; urethra and lower vagina in females)

27
Q

Development of the urinary bladder

A
  • Between weeks 4 and 6, mesonephric duct and ureteric bud incorporation into posterior wall of urinary bladder
  • Ureteric buds open into bladder wall, while the mesonephric ducts open more inferiorly into the pelvic urethra
  • The triangular region of the mesonephric duct incorporated in the bladder wall forms the trigone
28
Q

Exstrophy of the bladder

-Pathology?

A
  • Failure of midline closure of inferior abdominal musculature of anterior wall fails to form
  • Interior of bladder open to external environment
29
Q

Exstrophy of the bladder

  • Other characteristics
  • Females have?
A
  • Widely spaced pubic symphysis

- Females have a bifid clitoris

30
Q

Defects of the urinary bladder

-Four possible urachus anomalies-patent urachus?

A

An entirely tubular urachus connects the bladder to the umbilicus

31
Q

Defects of the urinary bladder

-Four possible urachus anomalies-urachal sinus?

A

The caudal urachus partially obliterates

32
Q

Defects of the urinary bladder

-Four possible urachus anomalies-Bladder diverticulum?

A

The proximal urachus partially obliterates

33
Q

Defects of the urinary bladder

-Four possible urachus anomalies-urachal cyst?

A

Caudally and proximally the urachus partially obliterates

34
Q

Defects of urinary bladder

A

Look at screenshots on ipad

35
Q

Congenital malformations of the ureter and kidney

A
  • Most do not cause clinical problems

- Because of inductive dependence, abnormalities of one structure often causes abnormalities in the other

36
Q

Bifid ureter-pathology?

A

Ureteric bud branches abnormally before it reaches the metanephric blastema

37
Q

Duplicate or ectopic ureter

-process?

A
  • Results from growth of two ureteric buds
  • Problems arise with bladder development original, caudal ureter opens normally
  • Cranial ureter follows mesonephric duct
38
Q

Ectopic ureter

-Found more often in which sex?

A

Females

39
Q

Ectopic ureter

-In females, the ectopic orifice may open into?

A

Vestibule (most common), urethra, vagina, or uterus

40
Q

Ectopic ureter

-In males, the orifice may open into?

A

-prostatic urethra, seminal vesicle, ejaculatory duct, or ductus deferens

41
Q

Ectopic ureter

-Ureters draining into bladder neck or prostatic urethra usually present as?

A

UTI and/or flank pain

42
Q

When ectopic ureters enter the male genital tract, what is common?

A

Epididymorchitis

43
Q

Unilateral renal agenesis

-Clinical detection of what could suggest unilateral renal agenesis?

A

-Clinical detection of unilateral absence of ductus deferens in males should suggest possibility of unilateral renal agenesis

44
Q

Both the absence of ductus deferens and unilateral renal agenesis could result from?

A

Absence or abnormality of mesonephric duct

45
Q

Unilateral renal agenesis

-Remaining kidney is more prone to?

A

Abnormality of position and rotation

46
Q

Bilateral renal agenesis

A
  • Incompatible with life
  • Oligohydramnios secondary to absence of intrauterine production
  • Associated hypoplastic lungs are usually responsible for death
  • Potter facies-increased width between eyes, flat nose, large low-set ears
47
Q

Renal dysplasia and agenesis

A
  • Failure of the kidney to develop uni- or bilaterally (agenesis) is due to the absence of inductive signals from the ureteric bud
  • Mutations in the gene(s) that regulate GDNF signaling, which controls branching and growth of the ureteric bud
48
Q

Congenital (infantile) polycystic kidney disease

-Characterized by?

A
  • Characterized by multifocal lesions of the proximal convoluted tubule, loop of henle
  • Result in dilation and cyst formation and destruction of the surrounding tissue
49
Q

Adult Polycystic Kidney

A
  • Nephron development is grossly disturbed

- Renal failure is usually present by middle age

50
Q

Wilms’ tumor

A
  • Cancer of the kidney
  • This usually affects children under the age of 5
  • Caused by mutations in the WT1 gene
51
Q

3 defects in partitioning of the cloaca

A
  • Failure of the Rathke folds to develop
  • Failure of both Tourneaux and Rathke folds to form
  • Misalignment of folds
52
Q

Urinary (and genital) system develops from?

A

Intermediate mesoderm of trilaminar disc

53
Q

What causes a rectovesical fistula to form?

A

Failure of both Tourneaux and Rathke folds to form

54
Q

Defects in partitioning of the cloaca

  • Failure of Rathke folds to develop results in what:
    • In males?
    • In females?
A

In males-Rectoprostatic urethral fistula

In females-rectocloacal canal or rectovaginal fistula

55
Q

Anorectal malformations

A
  • Imperforate anus is a malformation of the anorectal region that may occur in several forms
  • The rectum may end in a blind pouch that does not connect with the colon, or it may have openings to the urethra, bladder, or vagina
  • Anal stenosis or absence of the anus may be present
56
Q

Anal canal development

-Anorectal malformations?

A
  • Anorectal malformations are a spectrum of defects and are usually referred to as ‘low’ or ‘high’
  • Anal membrane fails to perforate
57
Q

Anal canal development

-Anal agenesis?

A

-Anal canal ends as blind sac BELOW pelvic diaphragm

58
Q

Anal canal development

-Anorectal agenesis (most common)?

A

-Rectum ends as blind pouch ABOVE the pelvic diaphragm

59
Q

High and low anorectal malformations

-Pics on slides 59 and 60

A

Look at pics

60
Q

Clinical prognosis

  • Imperforate anus
    • how is it corrected?
    • prognosis?
A
  • A colostomy is indicated after birth

- With surgical correction the prognosis is excellent

61
Q

Recto-urethral fistula

  - how is it corrected?
  - prognosis?
A
  • Colostomy before the definitive repair period

- The long-term prognosis for normal urethral and rectal function is good

62
Q

Rectovesical fistula

  - usually also have?
  - prognosis?
A
  • Usually also have poorly developed sacral bones and sphincters
  • The prognosis for normal bowel function is poor
63
Q

Partitioning of the cloaca

A

slides 54 and 55