Urinary System 1

Question 1

What does the paraxial mesoderm give rise to?

Answer 1

Somites

Question 2

What lies between the somites and lateral plate mesoderm?

Answer 2

A mesoderm component call intermediate mesoderm

Question 3

What is derived from the intermediate mesoderm?

Answer 3

Urinary Systems

Reproductive Systems

Question 4

What does the paraxial mesoderm induce?

Answer 4

Paraxial mesoderm induces kidney-forming ability of the intermediate mesoderm

Question 5

What are the three transcription factors that drive nephric tubule development?

Answer 5

Lim1

Pax2

Pax8

Question 6

Where are Lim1, Pax2 and Pax8 expressed?

Answer 6

In the intermediate mesoderm which lies between the somites and the lateral plate mesoderm

Question 7

What has occured upon evolution from lower forms to higher forms?

Answer 7

Development complexity of the kidney and its functional efficiency have vastly increased

Question 8

How does the urinary system develop?

Answer 8

In an organized fashion involving “generations” of nephric tubules

Question 9

What is the 1st generation of nephric tubule development?

Answer 9

Development in the cervical region of the embryo - representing the -pronephros

Question 10

What is the second generation of nephric tubules?

Answer 10

Development in the thoraco-lumbar region representing the -mesonephros

Question 11

What is the 3rd generation of nephric tubules?

Answer 11

Development in the sacral region representing the

-metanephros

Question 12

Of the 3 generations what is the most functional capable structure?

Answer 12

Metanephros

Question 13

What occus as the most caudal metanephros develops and becomes functional?

Answer 13

The pronephros and mesonephros atrophy

Question 14

What occurs at approximately time of somite development?

Answer 14

Cells of intermediate mesoderm in cervical region give rise to inner visceral layer and outer parietal layer.

Question 15

What is the cavity formed between inner visceral layer and outer parietal layer?

Answer 15

Nephrocele

Question 16

What are nephrotomes?

Answer 16

Cords of cells that grow out from parietal (dorsal) wall and form pronephric tubules

Question 17

What occurs at the distal end of each pronephric tubule?

Answer 17

Grows and extends laterally then moves caudally to fuse with same region of growing cells of the tubule right behind it

Question 18

What is the pronephric duct?

Answer 18

Site where distal end of each successive tubule fuses

Question 19

What occurs as more pronephric tubules form?

Answer 19

They fuse with the ever growing duct

THe duct grows toward the cloaca and becomes canalised (duct is initially solid)

Question 20

What does first glomeruli start as?

Answer 20

Starts as tufts of capillaries branching from dorsal aorta in pronephros

Question 21

Tufts push and invaginate into wall of pronephric tubule to form intermal glomeruli

Question 22

What is Bowmans Capsule

Answer 22

Invaginated epithelium around each glomerulus

Question 23

Funciton of internal glomerulus

Answer 23

Filtration producing a flitrate that moves to the pronephric tubule

Water and electrolytes are re-absorbed and waste products move to the pronephric duct then cloaca

Question 24

What is the urogential ridge?

Answer 24

Proliferation of intermediate mesoderm in the thoraco-lumbar region and projects into the peritoneal cavity

Question 25

When does the urogenital ridge begin to form?

Answer 25

Post-somite stage of development

Question 26

What develops around each mesonephric tubule?

Answer 26

Peri-tubular capillar network

Question 27

What does the peri-tubular capillary network aid in?

Answer 27

Greater capability of reabsorption of water and electrolytes

Question 28

How does mesonephros differ from pronephros?

Answer 28

Greater size Pronephros - one tubule at level of each somite Mesonephros - multiple mesonephric tubules at each somite

Question 29

What supplies blood to mesonephros and pronephros?

Answer 29

Dorsal aorta

Question 30

What two structure give rise to the metanephros form of the excretory organ?

Answer 30

Ureteric bud - outgrowth of mesonephric duct Region of Urinary ridge - Metanephric mass

Question 31

Where does development of metanephros take place?

Answer 31

Sacral region of the embryo

Question 32

What induces metanephric tissue to give rise to metanephric tubules?

Answer 32

Collecting ducts

Question 33

What influences final arrangement of kidney in mammals?

Answer 33

Manner in which widened end of ureteric buds develop

Question 34

What is the metanephric blastema or mass composed of?

Answer 34

Mesenchyme

Question 35

What is needed for survival of metanephric mesenchyme?

Answer 35

Ureteric bud

Question 36

What does GDNF do?

Answer 36

GDNF = Glial-derived neurotrophic factor - Secreted by mesenchyme and stimulates bud to become highly branched

Question 37

What do Wnt6 and Wnt 9b do?

Answer 37

Induce mesenchyme to form tubular epithelium which will be part of tubule

Question 38

What is the comma part of the tubule formation part of?

Answer 38

Develops into podocytes

Question 39

Function of podocytes?

Answer 39

Secret VEGF (vascular endothelial growth factor) - VEGF induces capillaries to branch and future formation of glomerulus