Development of Kidneys and Urinary Tract Flashcards Preview

ESA 3- Urinary System > Development of Kidneys and Urinary Tract > Flashcards

Flashcards in Development of Kidneys and Urinary Tract Deck (105)
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1
Q

What are the three sets of excretory organs in development of the kidneys and urinary tract?

A
  • Pronephros
  • Mesonephros
  • Metanephros
2
Q

When does the pronephros appear?

A

Start of week 4

3
Q

When does the pronephros regress?

A

End of week 4

4
Q

Is the pronephros functional?

A

No

5
Q

When does the mesonephros appear?

A

End of week 4

6
Q

When does the mesonephros regress?

A

End of week 8

7
Q

Is the mesonephros functional?

A

Yes

8
Q

Does the mesonephros have a water conserving mechanism?

A

No

9
Q

Where does the mesonephric duct have a very important role?

A

In the development of the male reproductive tract

10
Q

What does the mesonephric duct sprout?

A

The ureteric bud

11
Q

What is the ureteric bud?

A

The primordium of the collecting system of the definitive kidney

12
Q

When does the metanephros appear?

A

Week 5

13
Q

When does the metaneophros regress?

A

It doesn’t

14
Q

Is the metanephros functional?

A

Yes, from the end of the first trimester

15
Q

What is the metanephros?

A

The definitive kidney

16
Q

What does the collecting system develop from?

A

The ureteric bud

17
Q

What does the excretory system develop from?

A

The metanephric tissue cap

18
Q

What do the embryonic kidney and gonad originate from?

A

The urogenital ridge

19
Q

What is the urogenital ridge?

A

A region of the intermediate mesoderm

20
Q

Label this diagram

A
  • A - Paraxial mesoderm
  • B - Intermediate mesoderm
  • C - Somatic mesoderm
  • D - Intraembryonic coelom
  • E - Splanchnic mesoderm
21
Q

Label this diagram

A
  • A - Urogenital ridge
  • B - Mesonephric duct
  • C - Mesonephros
  • D - Gonad
22
Q

What does the organisation of the intermediate mesoderm lead to in the development of the kidneys and urinary tract?

A

3 systems developing sequentially

23
Q

What does the disapperance of one system in the development of the kidneys and urinary tract mark?

A

The start of then next

24
Q

Where does the first system in the development of the kidneys and urinary appear?

A

In the cervical region

25
Q

What is the first kidney system?

A

The pronephros

26
Q

What does the pronephros produce?

A

The pronephric duct

27
Q

Where does the pronephric duct extend?

A

From the cervical region to the cloaca

28
Q

What does the pronephric duct do?

A

Drives the development of the next stage, becoming the mesonephric duct

29
Q

Label this diagram, including what the red and yellow represents

A
  • A - Cloca
  • B - Pronephros
  • C - Mesonephros
  • D - Duct
  • E - Metanephros
30
Q

What does the mesonephros do?

A

Sprouts tubules that develop caudal to the pronephric region

31
Q

What makes up the embryonic kidney?

A

The tubules sprouted by the mesonephros and the mesonephric duct

32
Q

What does the mesonephric duct sprout?

A

The ureteric bud

33
Q

What does the ureteric bud do?

A

Induces the development of the definitive kidney

34
Q

Where does the mesonephric duct have an important role?

A

In the development of the reproductive system in the male

35
Q

Label this diagram

A
  • A - Mesonephros
  • B - Mesonephric duct
36
Q

Where does the ureteric bud sprout from?

A

The mesonephric duct

37
Q

What does the uteric bud do?

A

Induces the development of the definitive kidney within the intermediate mesoderm of the caudal region of the embryo that lies closest to it

38
Q

What happens once the ureteric bud has induced the development of the definitive kidney?

A

It expands and branches into differentiated intermediate mesoderm, the metanephric blastema

39
Q

What does the metanephric blastema form?

A

The definitive kidney’s structure

40
Q

What does the ureteric bud drive?

A

The development of the definitive kidney

41
Q

What is the collective system derived from?

A

The ureteric bud itself

42
Q

What is the excretory component derived from?

A

The intermediate mesoderm

43
Q

What is the development of the excretory component from the intermediate mesoderm under the influence of?

A

The ureteric bud

44
Q

Draw a diagram illustrating the role of the ureteric bud

A
45
Q

Where does the metanephric kidney first appear?

A

In the pelvic region

46
Q

What happens once the metanephric kidney has appeared in the pelvic region?

A

It undergoes an apparent caudal to cranial shift, crossing the arterial fork formed by vessels returning blood from the foetus to the placenta

47
Q

Do the kidneys actually move in development?

A

No

48
Q

Why do the kidneys not actually move in development?

A

Because development is cranial to caudal, and the trunk just extends downwards, making it appear as though the kidneys move

49
Q

What causes renal agenesis?

A

The ureteric bud fails to interact with the intermediate mesoderm

50
Q

What does renal agenesis affect?

A

One (unilateral) or both (bilateral) kidneys

51
Q

What are some congential abnormalities of kidney position and renal vessels?

A
  • Renal agenesis
  • Migration defect
  • Duplication defects
  • Cystic kidney disease
  • Abnormal renal vessels
  • Exstrophy of the bladder/urachal anomalies
  • Hypospadias
52
Q

What can cause a migration defect?

A
  • If a kidney fails to cross the arterial fork, it ends up much lower than it should be
  • During their ascent, the kidneys lie extremely close to one another. If they get caught on the arterial fork, they can fuse and form a horseshoe kidney
53
Q

Why may the kidney end up much lower than it should be if it fails to cross the arterial fork?

A

As the kidneys don’t actually move, its more the fork that snags the kidney as it develops, pulling it down

54
Q

Draw a diagram illustrating what happens if the kidney fails to cross the arterial fork

A
55
Q

Draw a diagram illustraing what happens if the kidneys fuse during their ascent

A
56
Q

What causes duplication defects?

A

Splitting of the ureteric bud, either partial or complete

57
Q

What is the systemic consequence of splitting of the ureteric bud?

A

An ectopic opening bypassing the bladder and causing incontinence

58
Q

Where may the ectopic opening occur in duplication defects?

A

Into the vagina or urethra

59
Q

Draw a diagram illustrating the consequence of a duplication defect

A
60
Q

What do the kidneys require as they ascend?

A

A new arterial supply

61
Q

Why do the kidneys require a new arterial suplply as they ascend?

A

Because the previous supply disappears

62
Q

What happens if the arterial supply to the kidneys remain after it has descended?

A

They are accessory, or supernumerary arteries

63
Q

What kind of arteries are the accessory arteries that remain after kidney ascention?

A

End arteries

64
Q

Why are the arteries that remain after ascention end arteries?

A

Because the main renal artery will not branch to supply that area of the kidney if an accessory artery is present

65
Q

What is the result of accessory end arteries in the kidney?

A

There is no collateral supply

66
Q

What is the bladder derived from?

A

The hindgut- the caudal portion of the primitive gut tube

67
Q

When is the bladder formed?

A

During embryonic folding in the fourth week of development

68
Q

What is the caudal portion of the bladder?

A

A dilated, blind pouch called the cloaca

69
Q

How is the cloaca separated from the outside?

A

By the cloacal membrane

70
Q

What is the cloacal membrane?

A

One of the two mesoderm-less regions left present after gastrulation

71
Q

What is the cloaca divided by?

A

The urorectal septum

72
Q

What is the cloaca divided into?

A

The urogenital sinus and the anorectal canal

73
Q

What is the urogenital sinus?

A

The future bladder and urethra

74
Q

What is the anorectal canal?

A

The future rectum and anal canal

75
Q

Label this diagram

A
  • A - Urinary tract
  • B - Gastrointestinal tract
  • C - Reproductive tract
76
Q

What is the allantois involved in?

A

The development of the bladder

77
Q

What is the allantois?

A

A superoventral diverticulum of the hindgut

78
Q

What does the allantois extend into?

A

The umbilical cord

79
Q

What happens to the lumen on the allantois?

A

It becomes obliterated to become the urachus

80
Q

What is the urachus in adults?

A

The median umbilical ligament

81
Q

Label this diagram

A
    • A - Hindgut
  • B - Urorectal septum
  • C - Urachus
  • D - Bladder and urethra
  • E - GI tract
82
Q

Draw a diagram of the urogenital sinus

A
83
Q

What are the stages in the development of the male bladder?

A
  1. Mesonephric ducts reach the urogenital sinus
  2. Ureteric bud sprouts from MD
  3. Smooth musculature begins to appear
  4. UGS begins to expand
  5. UBs and MDs make independant openings in UGS
  6. Prostate and prostatic urethra formed
84
Q

What do the mesonephric ducts do once they have reached the urogenital sinus?

A

Drain embryonic urine into the cloaca

85
Q

What does the ureteric bud become?

A

The ureter opening into the bladder

86
Q

What does the smooth musculature that appears in the embryonic bladder become?

A

The trigone of the bladder

87
Q

Is the MD maintained in the male?

A

Yes

88
Q

Why is the MD maintained in the male?

A

Because it forms the prostate and ducts of the male reproductive system

89
Q

Draw a series of diagrams illustrating the develoment of the male bladder

A
90
Q

How does the development of the female bladder differ from that of the male?

A

The female bladder develops in much the same way, but without male hormones, the mesonephric duct regresses

91
Q

What is the result of the regression of the mesonephric ducts in females?

A

Females do not form prostates or the tubes of the male reproductive system

92
Q

Draw a series of diagrams illustrating the development of the bladder in a female

A
93
Q

What is the female urethra formed by?

A

The pelvic part of the urogenital sinus

94
Q

What is the male urethra divided into?

A
  • Pre-prostatic
  • Prostatic
  • Membranous
  • Spongy
95
Q

What is the phallic part of the male urethra?

A

The spongy urethra

96
Q

What is true of the first three parts of the male urethra?

A

They are analogous to the female urethra

97
Q

What is exstrophy of the bladder?

A

A congenital anomaly in which part of the urinary bladder is present outside of the body

98
Q

What does exstrophy of the bladder occur due to?

A

Maldevelopment of the lower abdominal wall, leading to rupture that causes the bladder to communicate with the amniotic fluid

99
Q

What may exstrophy of the bladder be due to?

A

A urachal fistula

100
Q

What is a urachal fistula?

A

A patent urachus, which normally becomes the median umbilical ligament, remains as a duct and so connects the bladder to the umbilicus

101
Q

Draw a diagram illustrating a urachal fistula

A
102
Q

What is hypospadias?

A

A defect in fusion of urethral folds

103
Q

What happens in hypospadias?

A

The urethra opens onto the ventral surface, rather than the end of the glans

104
Q

What is happening to the incidence of hypospadias?

A

It is increasing

105
Q

Draw a diagram illustrating hypospadias

A