Embryology of Urinary System

Question 1

When does the urinary system form?

Answer 1

week 4

Question 2

What are the two parts of the urogenital system?

Answer 2

1. Urinary system

2. Genital system

Question 3

From what tissue does the urogenital system originate?

Answer 3

intermediate mesoderm

Question 4

T/F there are two slightly overlapping kidney systems?

Answer 4

False- there 3

Question 5

What are the three kidney systems and what is their purpose?

Answer 5

Pronephros- rudimentary, nonfunctional
Mesonephros- function for a short time during early fetal period
Metanephros- forms the permanent kidney

Question 6

When does the pronephros appear and degenerate?

Answer 6

Appears- day 21

Degenerates- day 24

Question 7

When does mesonephros appear?

Answer 7

early week 4- usually when the pronephros degenerates

Question 8

Where does the mesonephros develop/appear?

Answer 8

thoracic and lumbar segments of intermediate mesoderm

Question 9

In week _ the thoracic segments regress but the mesonephric kidney continues to function until week __.

Answer 9

5

10

Question 10

Urine travels from the mesonephros to the ____ via the ____ ____.

Answer 10

cloaca via the wolffian (mesonephric) duct

Question 11

In which direction does canalization take place?

Answer 11

Caudally to cranially

Question 12

Canalization initiates what?

Answer 12

The ureteric bud/metanephric diverticulum growth

Question 13

What day does the collecting portion- the ureteric bud- occur?

Answer 13

day 28

Question 14

The ureteric buds induce what?

Answer 14

the formation of metanephric blastema, which forms the glomeruli and tubules of the nephrons

Question 15

What happens if there is no ureteric bud? What about extra ones?

Answer 15

Kidney doesn’t develop

Supernumerary kidneys

Question 16

The stalk of the ureteric bud becomes what?

Answer 16

The ureter

Question 17

The kidneys ascend, T/F

Answer 17

Truth!

Question 18

When do the kidneys ascend?

Answer 18

Weeks 6-9

Question 19

Initially they kidneys form near the _____ ___ of the embryo.

Answer 19

caudal end

Question 20

Kidneys initially have their blood supply from the common iliac arteries. What happens during the ascent of the kidney?

Answer 20

New arteries will enter the hilum of the kidney

Question 21

As kidneys ascend, do they drag their blood supply with them?

Answer 21

Nope, new vessels come in as the old ones degenerate

Question 22

Pelvic kidney is the result of what?

Answer 22

The kidney doesn’t ascend- ectopic kidney

Question 23

Horseshoe kidney is a result of what?

Answer 23

The kidneys fusing together and running into the IMA, so it’s a little lower

Question 24

Supernumerary arteries of the kidney are a result of what?

Answer 24

… it’s fairly common, no big deal, as long as one of the extra arteries doesn’t push on the ureter

Question 25

The cloaca in the hindgut becomes divided by the _____ ____.

Answer 25

Urorectal septum

Question 26

The urorectal septum turns the cloaca into what two areas?

Answer 26

1. Ventral urogenital sinus

2. Dorsal anorectal canal

Question 27

The bladder forms from what portion of what?

Answer 27

The vesical portion of the urogenital sinus

Question 28

The urethra comes from what part of what?

Answer 28

The pelvic part of the urogenital sinus

Question 29

The distal portions of the mesonephric ducts and the attached ureteric ducts become incorporated into what?

Answer 29

The posterior aspect of the bladder

Question 30

The spongy part of the urethra come from the ____ part of the urgogenital sinus

Answer 30

phallic

Question 31

When the allatois is closed off/obliterated proximally, what is the obliterated part called?

Answer 31

The urachus

Question 32

What is a urachal cyst?

Answer 32

Part of the allantois is closed off, then its open for a small pocket, and then it’s regular

Question 33

What’s a urachal sinus?

Answer 33

It’s where the allantois is open and can drip urine out

Question 34

What’s a urachal fistula?

Answer 34

It’s not a sinus and it’s not a cyst, but it’s kinda like the allantois was never obliterated- there is no urachus