Embryology

Question 1

The urinary system develops from which germ layer

Answer 1

The intermediate mesoderm

Question 2

What is the pronephros

Answer 2

The ‘first’ kidney

Forms from segmented intermediate mesoderm

Question 3

Describe the mesonephric system

Answer 3

This is a temporary structure that forms from the intermediate mesoderm
Does function for a while
Develops into a long rod/duct that grows down the length of the embryo until it makes a connection with the cloaca

Question 4

What happens to the mesonephric tubules after week 10 of development

Answer 4

In women it regresses completely

In men some sections remain and become parts of the reproductive tract - e.g. vas deferens

Question 5

How many mesonephric tubules do you have in development

Answer 5

40 pairs that then regress to 20

Eventually all will regress

Question 6

What does the metanephros form

Answer 6

The uretic bud
Metanephric blastema
Will eventually form the permanent kidney

Question 7

Describe the development of the uretic bud

Answer 7

It develops from the distal part of mesonephric ducts
Then penetrates the metanephric blastema
This then takes over filtration

Question 8

What does the uretic bud go on to form

Answer 8

The collecting system: 
Ureter
Renal pelvis 
Major and minor calyces 
And the collecting ducts

Question 9

How do the calyces form

Answer 9

Initial branches from the bud come together and merge to form larger collecting spaces – intussusception
1st time this happens you get the major calynx
2nd gives you the minor one

Question 10

What is a nephron

Answer 10

Functional unit for the filtration of blood and production of urine

Question 11

What 4 parts make up a nephron

Answer 11

Bowman’s capsule
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule

Question 12

How do the nephrons develop

Answer 12

Development of collecting system triggers nearby metanephric tissue to start developing into nephrons
As it forms, one end forms connection with the vasculature and the other end connects to the collecting system

Question 13

The kidneys have to ascend during development - true or false

Answer 13

TRUE

they develop in the pelvis then move up to around L1 level

Question 14

What is kidney agenesis

Answer 14

Occurs if ureteric bud doesn’t connect to the kidney - therefore it wont function

Question 15

Is kidney agenesis survivable

Answer 15

If unilateral it is a survivable, if bilateral it isn’t

Question 16

What is a pelvic kidney

Answer 16

When the kidney doesn’t ascend to normal position

Can still function

Question 17

What is a horseshoe kidney

Answer 17

If the kidney come into contact whilst developing, they can fuse - forms a horseshoe shape
Get stuck under anterior branch of aorta (IMA) when it attempts to ascend

Question 18

Where does the bladder develop from

Answer 18

Cloaca forms the primitive urogenital sinus which goes on to form the bladder

Question 19

What does the primitive urogenital sinus form

Answer 19

Bladder
Pelvic Urethra
Definitive Urogenital Sinus