Lecture 19 - Embyrological Development

Question 1

What embryonic layer gives rise to the kidneys?

What part of this embryonic layer in particular?

Answer 1

Mesoderm

Intermediate mesoderm

Question 2

What are the 3 systems that develop sequentially leading to the formation of the kidneys?

Answer 2

Pronephros
Mesonephros
Metanephros

Question 3

What region of the embryo does the pronephros first arise in?

Answer 3

Cervical region

Question 4

Which embryonic layer gives rise to the bladder??

Answer 4

Endoderm

Question 5

What is the purpose/function of the pronephros?

Answer 5

Has no function (not used)

Gives rise to the pronephric DUCT

Question 6

How does the pronephric duct travel in the embryo?

Answer 6

From the cervical region where it’s formed down to the cloaca

Question 7

What is the importance of the pronephric duct?
How does the name of the duct change and why?

Answer 7

Gives rise to mesonephric tububles caudal to the duct

As the pronephros degenerates it becomes the mesonephric duct

Question 8

What 2 structures are considered the embryonic kidney?

What can this structure do?

Answer 8

Mesonephric tubules + Mesonephric duct = embryonic kidney

Can filter stuff out of body but can’t conserve water

Question 9

What important structure does the mesonephric duct sprout/give rise to?

Answer 9

Ureteric bud

Question 10

What does the ureteric bud give rise to?

Answer 10

Metanephros/kidney

Question 11

What other important system (except for the urinary system) does the mesonephric duct have an important role in developing?

Answer 11

Male reproductive system

Question 12

What is the name of the tissue which releases growth factors leading to the formation of the ureteric bud from the mesonephric duct?

Answer 12

Metanephric blastema

Question 13

What structure gives rise to the collecting system?

What structure gives rise to nephrons?

Answer 13

Ureteric bud = collecting system

Metanephric blastema = nephron

Question 14

What is considered the collecting system formed by which structure?

Answer 14

Ureteric bud

Collecting duct, major calyces, minor calyces and ureters

Question 15

What structure forms the collecting system?

What is considered the collecting system?

Answer 15

Ureteric bud

Collecting duct, major calyces, minor calyces and ureters

Question 16

What anatomical location does the Metanephric kidney first appear in?

Answer 16

Pelvic region

Question 17

How does the Metanephric kidney migrate? (where does it end up?)

What structures does it take with it as it does so?

Answer 17

Moves from caudal end to cranially
It takes arteries from teh aorta as it ascends to sit under the adrenal glands

Question 18

What congenital defect can occur if the ureteric bud fails to interact with the intermediate mesoderm/Metanephric blastema?

Answer 18

Renal agenesis
(Kidneys dont form)

Question 19

What are some other defects that can occur with kidney development that isn’t renal agenesis?

Answer 19

Abnomral migration
Duplication defects
Ectopic ureter
Cystic disease

Question 20

What is a pelvic kidney?

Answer 20

When a kidney gets trapped in the pelvic region

Question 21

What is a horseshoe kidney?

Answer 21

When the poles of the kidney fuse together so they’re in in the shape of a big horseshoe
This means they get caught by the inferior mesenteric artery on ascent

Question 22

What artery does a horseshoe kidney get stuck on on ascent?

Answer 22

Inferior mesenteric artery

Question 23

What may happen if the ureteric bud splits too early?

Answer 23

Ectopic urethral openings
2 renal pelvises connecting to 1 ureter
Or 2 ureters connecting to 1 renal pelvis

Question 24

What is the dilated structure at the end of the hindgut called?

Answer 24

Cloaca

Question 25

What structre does the bladder and urethra come from?

Answer 25

Cloaca

Question 26

What is the important structure that separates urinary (bladder and urethra) development from GI tract development in the hindgut?

Answer 26

Urorectal septum

Question 27

What structures does the urorectal septum separate?

Answer 27

Urogential sinus
Anorectal canal

Question 28

What is the urachus?

What is the allantois?

Answer 28

Structure continuos with the urogential sinus formed from the Allantois

Structure where urine was initially drained from in the 1st trimester

Question 29

What 3 parts is the urogenital sinus split into?

Answer 29

Superior part connecting to umbilicus
Middle/pelivc part
Inferior/caudal part

Question 30

What does the superior pat of the Urogential sinus form?

Answer 30

Bladder

Question 31

What does the pelvic part of the urogenital sinus form?

Answer 31

Females = urethra and some reproductive tract
Males = prostatic + membranous urethra

Question 32

What does the caudal/inferior part of the Urogential sinus form?

Answer 32

Females = part of female repro tract
Males = spongy urethra

Question 33

What part of the female reproductive tract is formed by teh lower part of teh urogential sinus?

What about male?

Answer 33

Clitoris
Penis/spongy urethra

Question 34

Briefly describe the formation of the female bladder and urethra:

Answer 34

Mesonephric ducts reach urogential sinus
Ureteric bud sprouts from mesonephric ducts
Urogenital sinus expands and mesonephric duct regresses
Ureteric bud opens into urogenital sinus

Question 35

What structure is formed by the mesonephric duct being absorbed/drawn into the bladder??

Answer 35

Trigone

Question 36

Briefly describe the formation of the male bladder and urethra

Answer 36

Mesonephric ducts (MD) reach urogenital sinus (UGS)
Ureteric bud sporuts from MD
Smoooth muscle appears and UGS expands
UB and MD make independant openings in UGS (trigone)

Question 37

Which stage of kidney development forms the Trigone?

Answer 37

Mesonephros

Question 38

What week of development is the kidney functional and ascending to secreted urine?

Answer 38

Week 10

Question 39

What week of development is the pronephros degraded by?

Answer 39

Week 4