Embryology

Question 1

Whats the role of kidneys pre-natally?

Answer 1

Prenatally, the renal system produces amniotic fluid

Question 2

What is oligohydramnions?

Answer 2

lack of amniotic fluid

Question 3

What is a complication of oligohydramnions?

Answer 3

Potter syndrome: a series of abnormalities resulting from oligohydramnios, usually secondary to bilateral renal agenesis (BRA).

Question 4

What is the embryological origin of kidneys?

Answer 4

Intermediate mesoderm are the origin of kidneys

Question 5

What is the intermediate mesoderm an extension of?,

Answer 5

intraembryonic coleom, and in- trenches the dorsal aorta from either sides

Question 6

Where does the bladder originate from?

Answer 6

primitive gut tube (ie. cloaca)

Question 7

Whats the difference of pronephros and mesonephros?

Answer 7

Pro - blood filtered in the cavity

Meso - glomerulus integrated into nephron

Question 8

What are the temporary and early kidney system in embryos?

Answer 8

Mesonephros at C7/T1 –> T5 (for weeks 6-10)

Question 9

T or F: mesonephric ducts extend toward the cloaca

Answer 9

T

Question 10

How is the mesonephric tubules formed?

Answer 10

From the mesonephric duct, tubules extend to the adjacent intermediate mesoderm

Question 11

With what do the mesonephric ducts fuse?

Answer 11

the posterior wall of the urogenital sinus (part that will become bladder).

Question 12

Whats the effect of adjacent mesonephrenic duct on the adjacent intermediate mesoderm?

Answer 12

becomes epithelial and forms a vesicle

Question 13

Where does the vesicle fuse?

Answer 13

Fuses with mesonephric duct

Question 14

What happens to dorsal aorta after fusion of vesicle with duct?

Answer 14

The dorsal aorta sends off a branch, which forms a tuft of capillaries adjacent to the mesonephric tubule.

Question 15

What is the structure called when the mesonephric tubule curves around the glomerulus?

Answer 15

Bowman’s capsule

Question 16

What are the sources that give off the metanephros?

Answer 16

Develops from 2 sources:

1) Ureteric bud branches off caudal mesonephric duct (sacral region). Forms the collecting duct system of the kidney.
2) Metanephric blastema develops from mesenchyme in intermediate mesoderm adjacent to ureteric bud.

Forms the nephrons of the kidney.
Ureteric bud appears on day 28. Metanephros starts to function in week 10, but continues to produce new nephrons until week 32.

Question 17

What happens if signalling between metanephric blastema and ureteric bud does not occur?

Answer 17

if either ureteric bud or metanephric blastema fail to form, no kidney is made

Question 18

When does the ureteric bud start to branch?

Answer 18

Once the ureteric bud enters the metanephric blastema, it undergoes multiple rounds of branching

Question 19

The branching of the uteric bud leads to what structure?

Answer 19

The proximal portions of the collecting duct system.

Question 20

Where do nephrons originate from?

Answer 20

blastema

Question 21

T or F: lower number of nephrons leads to increased risk of renal disease later in life

Answer 21

T

Question 22

When does nephrogenesis end?

Answer 22

Nephrogenesis is finished shortly before birth.

Question 23

What are the anomalies of ureteric bud and metanephric blastema?

Answer 23

1. Supernumerary kidney
2. Bifid ureter:
3. Ectopic ureter

Question 24

What is a supernumerary kidney?

Answer 24

metanephric blastema divided into two parts following first branching of ureteric bud.
(three kidneys)

Question 25

What is a bifid ureter?

Answer 25

ureteric bud branched before entering metanephric blastema

two ureters that coverge leading to bladder

Question 26

What is a ectopic ureter?

Answer 26

two ureteric buds formed and only one can enter bladder at normal site.

Question 27

T or F: kidneys undergo active migration to reach the final destination

Answer 27

F:

Kidneys “ascend” due to differential body growth (not an active migration).

Question 28

Where does the renal artery branch off of when kidneys at pelvic area?

Answer 28

common illiac artery

Question 29

What becomes of the three segments of the urogenital sinus?

Answer 29

Bladder segment is the expanded part of the urogenital sinus.

Pelvic segment is the narrow neck and becomes the pelvic urethra.

Phallic segment contributes to penile urethra in men and vestibule of vagina in females.

Question 30

What happens if allantois fails to completely degenerate into a fibrous cord?

Answer 30

may be left with a urachal cyst or fistula (this happens if there is a blockage of the urethra)

Question 31

What can cause vesicoureteral reflux?

Answer 31

Defects of the ureterovesical (ie. where the ureter meets the bladder)

Question 32

What are the fate of mesonephric ducts?

Answer 32

Fate of mesonephric ducts:
vas deferens in the male
degenerates in female.