kidney formation

Question 1

which germ disc does the kidney arise from?

Answer 1

mesoderm

Question 2

which area of the mesoderm?

Answer 2

intermediate mesoderm

Question 3

what forms in the intermediate mesoderm? + when

Answer 3

pronephros, mesonephros and metanephros

Question 4

what structure will form the definitive kidney?

Answer 4

metanephros

Question 5

first structure formation stages

Answer 5

1. pronephros develops in the cervical region of the embryo
2. the epithelial cells arrange themselves in a series of tubules called nephrotomes and join laterally with the pronephric duct
3. pronephros then develops in the caudal direction

Question 6

what appears next?

Answer 6

mesonephros then develops

Question 7

stages of mesonephros formation

Answer 7

1. pronephros tubules in the thoracolumbar region induces intermediate mesoderm to become epithelial mesonephric tubules
2. each mesonephric tubule receives a blood supply from the aorta ending in a capillary tuft
3. allows for filtration, resulting in the filtrate becoming drained
4. pronephros degenerates a the mesonephros moves caudally, attaching to the cloaca

Question 8

what forms at the attachment of the mesonephros to the cloaca?

Answer 8

an out pouching called the uteric bud

metanephrogenic diverticulum

Question 9

which way does the uteric bud grow?

Answer 9

posteriorly and upward towards head

Question 10

what is this elongated stalk called?

Answer 10

the metanephric duct

Question 11

what does it go on to form?

Answer 11

the ureter

Question 12

what happens next to the metanephros?

Answer 12

1. moves into the intermediate mesoderm
2. undergoes a series of branchings to form the collecting duct system of the kidney and the major and minor calyces of the renal pelvis

Question 13

what is the metanephrogenic blastema?

Answer 13

region of intermediate mesoderm in contact with tips of the developing uterc bud

Question 14

what happens to the metanephrogenic blastema?

Answer 14

1. uteric bud releases signals inducing the differentiation of the intermediate mesoderm
2. this forms renal tubules
3. the renal tubules then grow and come into contact with the connecting tubules

Question 15

explain sequence of divisions of uteric bud?

Answer 15

renal pelvis- 4 more- branches to major calyces, 4 more of major calyces to form mid calyces- more to collecting duct tips

Question 16

final process to form definitive kidney

Answer 16

tips of collecting ducts swell to form ampullae

the ampullae induce surrounding mesenchyme to undergo EMT to form nephrite cap and nephrogenic vessels

Question 17

where do the kidneys form?

Answer 17

near the bladder

Question 18

what happens next to the kidneys?

Answer 18

ascend in weeks 6 and 9 due to differential growth

change their blood supply as they ascend

Question 19

cancer in the kidney

Answer 19

Wilm’s tumour

Question 20

explain Wilm’s tumour

Answer 20

develop from kidney remnants

Question 21

what structure leads to the formation of the bladder?

Answer 21

allantois and the distal ends of the mesonephros

Question 22

explain development of bladder

Answer 22

1. rectum and ventral part of cloaca separated, forming the primary urogenital sinus which forms the bottom of the bladder
2. this joins to the mesonephros remnants
3. this joins to the allantois
4. the caudal ends of the renal diverticula join the allantois to form the trigone

Question 23

what does the mesonephros go onto form?

Answer 23

wolffian ducts of the male reproductive system