Session 2 - Embryology Flashcards Preview

Semester 3 - Urinary > Session 2 - Embryology > Flashcards

Flashcards in Session 2 - Embryology Deck (61):
1

What tissue in the tri-laminar disc does the kidney develop from?

• Intermediate mesoderm

2

What are the two areas post-gastrulation where there is no mesoderm between ecto and endoderm?

• The buccopharyngeal membrane (oral cavity)
• Cloacal membrane (anus)

3

How is the intermediate mesoderm organised?

• 3 systems develop sequentially
• Disappearance of one system marks the onset of development of the next

4

What is the first part of the renal system to develop?

• The pronephros

5

What is the second part of the renal system to develop?

• The mesonephros

6

What is the third part of the renal system to develop?

• The metanephros

7

What four structure make up a nephrotome?

• Glomerulus
• Bowman's capsule
• Proximal & distal convoluted tube
• Collecting duct

8

What is the pronephros?

• First kidney system in humans

9

What is the function of the pronephros?

• No direct function
• Provides pronephric duct which extends from the cervical region to the cloaca and drive the development of the mesonephros (becomes mesonephric duct)

10

What is the urogenital ridge?

• Region of intermediate mesoderm giving rise to both the embryonic kidney and the gonad

11

Is the mesonephros a functional kidney?

• Yes, but has no water conserving mechanism
• Has a very important role in the development of the male reproductive tract

12

What makes up the embryonic kidney?

• The mesonephros
• Made up of mesonephric tubules and the mesonephric ducts

13

In what direction do the mesonephric tubules develop?

Caudal to pronephric

14

Why is the mesonephros only thought of as a partial kidney?

• Can produce urine, but cannot concentrate it

15

How does the mesonephric duct drive the development of the definitive kidney?

• Sprouts the ureteric bud

16

Aside from driving the development of the definitive kidney, give a role of the mesonephric duct

• Drives development of male reproductive system

17

Where does the ureteric bud induce development of the definitive kidney?

• Within the intermediate mesoderm of the caudal region of the embryo

18

What is the collecting system of the kidney derived from?

• The ureteric bud

19

What is the excretory component of the kidney derived from?

• The metanephric tissue cap
• Intermediate mesoderm under the influence of the ureteric bud

20

What is the ureteric bud the primordium of?

• The ureter
• Renal pelvis
• Calices
• Collecting tubules

21

What is the "ascent" of the kidney?

• The metanephric kidney first appears in the pelvic region
• Undergoes an apparent caudal to cranial shift, crossing the arterial fork formed by vessels returning blood from the fetus to the placenta

22

Do the kidneys truly ascend?

• No, body undergoes cranial to caudal shift around them

23

What happens to blood supply of the kidney during ascendion?

• Kidneys receive blood from those arteries closest to them

24

Why is variation in renal blood supply so common?

• Due to the kidneys constantly changing blood supply during development
• Additional renal arteries may be present, or superior or inferior pole vessels

25

When would hydronephrosis occur?

• As a result of an inferior pole artery obstructing the ureter

26

What happens if the ureteric bud fails to interact with intermediate mesoderm?

• Renal agenesis will occur

27

What is one sided renal agenesis called?

Unilateral

28

Give five ways other ways things go awry in kidney development?

• Migration goes wrong
• Wilm's tumour
• Duplication defects
• Ectopic ureter
• Cystic disease

29

Outline a migration defect of the kidney

• If kidney fails to cross the arterial fork, it will end up lower than it should
• If this happens to both kidneys, a horseshoe kidney may appear due to fusion

30

How can duplication errors occur (e.g. 2 ureters)?

• Splitting of the ureteric bud (partial or complete)

31

What problems occur if there is an extra ureter?

• Ectopic drainage can occur into vagina urethra
• Main symptom will be incontinence

32

What is polycystic kidney disease?

• Recessive genetic disease which presents early and has a poor prognosis

33

What defect can occur in multicystic kidney disease?

• atresia of ureter

34

Give three facts about polycystic kidney disease?

• Recessive
• Presents early
• Poor prognosis

35

How do abnormal renal vessels appear?

• As kidneys ascend they required new arterial supply, and the previous supply disappears
• If they remain, they become accessory or supernumerary arteries
• If these arteries are present, renal artery will not branch and form collateral circulation

36

What is the cloaca?

• Part of the primitive gut tube shared by GI, urinary and reproductive tracts
• Dilated, blind pouch

37

How is the cloaca separated from the outside?

• By the cloacal membrane

38

What is the urogenital sinus?

• Cloaca divided by urorectal septum
• Continuous with umbilicus

39

What is the urogenital sinus responsible for the genesis of?

• Bladder, pelvic and phallic parts

40

Outline the development of the male urinary tract

• Mesonephric ducts reach urogenital sinus
• Ureteric buds spout from MD
• Smooth musculature begins to expand, urogenital sinus begins to appear
• Ureteric bud and mesonephric ducts make independent openings in urogenital sinus
• Prostate and prostatic urethera formed

41

Where is the bladder derived from?

• The hindgut

42

What is the function of the mesonephric duct in males?

• Forms part of reproductive tract

43

How is the cloaca divided?

• By the urorectal septum

44

What does division of the cloaca by the urorectal cloaca form?

• Urogenital sinus (future bladder and urethera)
• Anorectal canal

45

What is the allantois?

• A superoventral diverticulum of the hind gut which extends to the umbilicus

46

What does the allantois become and how?

• Lumen of the allantois becomes obliterated to become the urachus
• Urachus becomes the median umbilical ligament in adults

47

Outline the development of the male urinary tract

• Mesonephric ducts reach urogenital sinus
• Ureteric buds spout from mesonephric duct
○ Ureteric bud will become ureter opening into bladder
• Smooth musculature begins to expand, UGS begins to expand
• Ureteric buds and mesonephric ducts make independent openings in UGS
• Prostate and prostatic urethera formed. MD is maintained in the male, forming prostate and seminal vesicles.

48

What is the epithelium of the bladder derived from?

• The endoderm of the urogenital sinus
• EXCEPT for trigone, which is derived from distal ends of mesonephric ducts

49

Give the four divisions of the male urethera

• Pre ‐ prostatic
• Prostatic 
• Membranous
• Spongy

50

Where are the first three parts of the male urethera formed from?

• Pelvic part of urogenital sinus

51

What is the spongy part of the urethera formed from?

• Phallic part of UGS

52

Give the three basic components of the external genitalia

• Genital tubercle
• Genital folds
• Genital swellings

53

What happens to the genital tubercle in the male?

• Elongates and genital folds to form the spongy urethera

54

How does formation of the female bladder differ from in the male?

• Without male hormones, the mesonephric duct regresses

55

What is hypospadias?

• Defect in fusion of uretheral folds
• Urethra opens onto the ventral surface rather than at the end of the glans
• Incidence increasing (WHY)

56

Give three ways in which bladder and urethera can go wrong?

• Fistulae
• Exstrophy of the bladder
• Ectopic urethral orifices

57

What is exstrophy of the bladder?

• Congenital anomaly in which part of urinary bladder is present outside of the body
• Due to maldevelopment of lower abdominal wall

58

How may exstrophy of the bladder be due to a urachal fistula?

• A patent urachus, which normally becomes the median umbilical ligament
• If it remains as a duct, it will connect the bladder to the umbilicus

59

Where do the metanephric kidneys initially lie?

• Close to each other in the pelvis, ventral to the septum

60

What does the ascent of the kidneys stem from?

• Growth of the embryo's body caudal to the kidneys

61

What happens to the hilum of the kidney as it develops?

• It initially faces ventrally (forward), but rotates medially almost 90 degrees.