Embryology

Question 1

What embryological tissue type makes up the urinary system?

Answer 1

Intermediate plate mesoderm forms the urinary and reproductive systems (GU system)

Question 2

Define the allantois

Answer 2

The allantois is an outpouching of endoderm at the hindgut that extends into the body stalk

Question 3

Define the cloaca

Answer 3

• The cloaca is the single posterior opening for a bird’s digestive, urinary and reproductive tracts and is used to expel faeces and lay eggs.
• Also found in human embryos before relevant structures have developed

Question 4

What do you call the outpouching of endoderm at the hindgut that extends into the body stalk?

Answer 4

Allantois

Question 5

What type of tissue is the allantois?

Answer 5

Endoderm

Question 6

What type of tissue is the cloaca?

Answer 6

Intermediate mesoderm

Question 7

What does the urogenital sinus form in developed embryos?

Answer 7

The urogenital sinus later forms the urinary bladder proximally and its caudal end forms the urethra

Question 8

What forms the urachus?

Answer 8

Allantois will eventually become clamped, but will form urachus post-embryonically

Question 9

What does the allantois form post-embryonically?

Answer 9

Urachus

Question 10

What is the first primitive set of kidneys called?

Answer 10

Pronephros

Question 11

What does the pronephros duct drain into?

Answer 11

Cloaca

Question 12

When during development is the pronephros present?

Answer 12

Between week 4-5

Question 13

What is the second primitive set of kidneys called?

Answer 13

Mesonephros

Question 14

When during development is the pronephros present?

Answer 14

Week 5-9

Question 15

What is the third primitive set of kidneys called?

Answer 15

Metanephros

Question 16

Describe the development and embryological origins of the gonads

Answer 16

Much of the mesonephros will then be incorporated into the developing gonad (as well as undifferentiated cells from the yolk sac which migrate in to form the spermatogonia/ oogonia)

Question 17

What do the mesonephric tubules and duct become in males?

Answer 17

In males, the mesonephric tubules become the rete testis and the mesonephric duct becomes the vas deferens

Question 18

What do the mesonephros and the mesonephric tubules become in females?

Answer 18

In females the mesnephros becomes the ovary but the tubules and mesonephric duct degenerate

Question 19

What does the ureteric bud and its stalk become?

Answer 19

• The ureteric bud from the mesonephric duct undergoes repeated branching at its distal end.
• The stalk of this bud becomes the ureter and the expanded cranial end becomes the renal pelvis.

Question 20

What makes up a nephron?

Answer 20

Nephron = Renal corpuscle + PCT + Loop of Henle + DCT

Question 21

What makes up a uriniferous tubule?

Answer 21

Uriniferous tubule = Nephron + Collecting duct

Question 22

What does the nephron develop from?

Answer 22

Nephron develops from metanephric mesoderm

Question 23

What does the collecting duct and tubules, the renal pelvis and the ureters develop from?

Answer 23

Collecting duct and calyces, pelvis, ureter develop from the ureteric bud

Question 24

Describe the ascent of the kidneys

Answer 24

• Kidneys initially lie on either side of the bladder and in the developing pelvis.
• Appears to “ascend” into the abdomen mainly due to differential growth of lower body inferiorly away from kidneys

Question 25

At what vertebral levels are the adult kidneys found?

Answer 25

T12-L3

Question 26

When do kidneys stop ascending?

Answer 26

When they reach the adrenal glands

Question 27

What % of the population have an accessory renal artery?

Answer 27

25%