4. Renal Embryology

Question 1

Intermediate mesoderm comes into play for the urogenital system. The urogential ridge which contains the gonadal ridge (testes and ovaries are formed). There is also a nephrogenic cord which becomes?

Answer 1

Becomes the nephron which produce urine

and the ducts: collecting system

Question 2

What does the mesonephric tubule give rise to?

Answer 2

the nephron which gives rise to the urine

Question 3

What are the three different kidneys that are produced during the production of the kidneys?

Answer 3

1st : Prenephros (non functional)

2nd: Mesonephros (functional)
3rd: Metanephros (true)

Question 4

How big are the kidneys in the emrbyo?

Answer 4

they run the length of the embryo

Question 5

The pronephros is the first kidney that forms during the 4th week in the cervical region of the embryo and then degenerates in late week 4. What does it form?

Answer 5

Forms the pronephric ducts and tubule which connects all the way down to the cloaca
(rudimentary- no function)

Question 6

The mesonephros is the second kidney that appears late in the fourth week and is remodeling in late week 11/12. The mesonephros is remodeling into?

Answer 6

male genitalia for males and is decinegrated in females

Question 7

The mesonephric duct is the pronephric duct that goes to the cloaca, which contains mesonephric tubules that do?

Answer 7

fucntional that form urine and drain to cloaca

Question 8

The metanephros is the third and final adult kidney. Begins development in week 5, functional. it contains the ureteric bud (metanephric duct/metnephric diverticulum) which does what?

Answer 8

forms in the pelvis with the metnephrogenic blastema/mass/cap from intermediate mesoderm which give rise to the nephron and the collecting system for true kidney

Question 9

The nephron of mesonephros is the functional unit which consists of the glomeruli (from the dorsal aorta), bowmans capsule and mesonephric tubules which are from intermediate mesoderm. The mesonephric duct does what?

Answer 9

induces generation of nephrons in adjacent nephrogenic cord, send signals to form the mesonephric vesicle, which also signals back to the duct

Question 10

The mesonephric vesicle elongates into ?

Answer 10

a mesonephric tubule which meets with the mesonephric duct

Question 11

The mesonephric tubule will continue to elongate and wrap around the glomerulus which forms?

Answer 11

the glomerular capsule around the glomerulus, along with the duct and tubule fully connecting

Question 12

The metnephros (ureteric bud and metanephric blastema) which form in the pelvis.** The ureteric bud grows out of the mesonephric duct. ** The ureteric bud will grow towards?

Answer 12

the metanephric blastema and sends signals to form the vesicles/tubules, which then signals back to the bud as well.

Question 13

The ureteric bud gives rise to what from intermediate mesoderm? (5)

Answer 13

ureter
pelvis
major calyces
minor calyces
collecting tubules

Question 14

The metanephric blastema which is from the nephrogenic cord (intermediate mesoderm) forms what structures? (5)

Answer 14

Renal vesicles
bowman’s capsules
proximal/distal convoluted tubules
loop of henle

Question 15

For the collecting system, the ureteric bud contacts the blastema and will give rise to the pelvis (both send signals to eachother). The ureteric bud will bifurcate and form?

Answer 15

form branches which coalesce (condense) on themselves to form the major calyces. 2nd generation they will branch again from the major calcyes and coalesce to form the minor clayces

Question 16

The branching will continue to give you collecting ducts. Collecting ducts will send signals to the metnephrogenic blastema to induce the formation of the nephric vesicle. What occurs to the nephric vesicle?

Answer 16

it elongates and then invaginates around the glomerulus forming the bowmans capsule.

It will also connect to the collecting duct and form the rest of the renal nephron structures

Question 17

Unilateral renal agenesis, males more affected, and many times more the left kidney affected. The other kidney hypertrophies and takes on the role for both. What is looked for during an ultrasound at week 20?

Answer 17

when there is only one umbilical artery

Question 18

Bilateral renal agenesis is when there are no kidney structures. This could be mainly due to?

Answer 18

oligohydramnios- lesser fluid, associated with lung hypoplasia. 20% of these cases are related to the Potter sequence (many other problems)

Question 19

What is the embryological mechanism is associated with bilateral renal agenesis?

Answer 19

the metanephros — ureteric bud didnt develop or it didnt get signal from blastema and then regressed

Question 20

A duplex kidney results from abnormal division of the ureteric bud. How do these patients present?

Answer 20

with a double kidney with two ureters

Question 21

While the metanephros is forming, the mesonephros is still there. During the 9th week of fertilization what occurs?

Answer 21

The metanephros accend into the adult position due to caudal growth

Question 22

The hilum starts anteriorly and rotates towards the aorta in the middle of the body. What does this mean?

Answer 22

the kidneys rotate 90º

Question 23

What is the blood supply to the kidneys?

Answer 23

Whereever they are at the time is where they are getting their blood from. EX: pelvic area: common iliac
aorta, once ascended

Question 24

Pelvic kidneys are ectopic kidney (not located in the right spot). Why do pelvic kidneys occur? (one kidney is ascended correctly and the other is not)

Answer 24

the kidney does not ascend due to the cardinal vessels preventing it from ascending

Question 25

A horseshoe kidney is when the inferior poles of the kidneys fuse together, and when they try to ascend, they do not. Why holds the kidneys from acending?

Answer 25

The inferior mesenteric artery (IMA) off of the aorta to L3, which stops the kidney from migrating to L2

Question 26

Accesory renal vesels are vesels that come from aorta to the kidney (end arteries are the only vessel suppplying that certain tissue). What is common problem associated with accessory renal vessels?

Answer 26

They commonly cross over the ureters to connect to the aorta which can compress the ureters causing an obstruction

Question 27

Cystic kidney disease and an AR disease where there are multiple small cysts in both kidneys due to a mutation in PKHD1. What does this lead to?

Answer 27

renal insufficiency and 25% cases have lung hypoplasia which are both due to oligohydramnios

Question 28

Multicystic dysplastic kidney disease is due to cysts that are wide dilations of the loop of henle usually only affecting one kidney. What occurs?

Answer 28

So people are asymptomatic, there are fewer cyst present compared to the other cystic disease. Other kidney picks up the slack

Question 29

The ureter is derived from mesonephric and later the metanephric ducts. ** IN THE ADULT THE URETERS ONLY COME FROM THE METANEPHRIC DUCT/URETERIC BUD** The ureteric bud grows out of the mesonephric duct and then what does the mesonephric duct do?

Answer 29

it is incorporated into the posterior bladder wall and then the ureteric bud becomes the metanephric duct to form the ureter

Question 30

All of the bladder is made up of hindgut endoderm except for which region?

Answer 30

the trigone (incorportation of mesonephric duct into the bladder wall) is made up of mesoderm

Question 31

The bladder is from hindgut endoderm. The cloacal membrane is made of endo/ectoderm and will rupture. The cloacal membrane needs to be separated into? (2)

Answer 31

the urogential membrane and anal membrane via the urorectal septum

Question 32

The urorectal septum (MESODERM) does what when it migrates?

Answer 32

it separates the urogenital system (above urorectal septum) from the rectus (below), forming the urogential membrane and anal membrane- both are endo/ectoderm

Question 33

The allantois is an extension of hindgut endoderm from the bladder and goes into the umbilical cord. It then becomes the urachus which in the adult does?

Answer 33

it flattens out and becomes the medial umbilical ligament (abdomen stuff)
clinical problems

Question 34

The urogenital sinus (bladder= hindgut endoderm) consists of 3 different regions, including?

Answer 34

vesicle part
pelvis part
phallic part

Question 35

The vesicle part gives rise to the bladder. The pelvis part gives rise to the urethra in females and prostatic and membranous urethra in males. What does the phallic part give rise to?

Answer 35

lining of the vaginal vestibule in females and spongy urethra in males

Question 36

When the allantois does not flatten out to form the median umbilical ligament, a urachal fistula can form. What happens?

Answer 36

abnormal connection to the belly button, allowing urine to leak out of the belly button during urination

Question 37

A urachal cyst is when a portion of urachus is maintained and forms a cyst… how is it found?

Answer 37

usually causes no problems, found during autopsy

Question 38

A urachal sinus is when there is a deep belly button, with some pathology in men can cause?

Answer 38

pressure in bladder which can open it up and create a urachal fistula

Question 39

Exstrophy of the bladder (ectopic vesicae) is when the bladder is on the outside of the anterior abdominal wall. What would cause this to occur?

Answer 39

during week 4 due to defecttive mesoderm migration to anterior abdominal wall as body walls were forming, need abdomal wall to signal bladder closure, so bladder is open as well

Question 40

Epispadias is improper location of genital tubercles caudal to cloacal membrane. Where would this opening be?

Answer 40

opening is on the dorsal side of the penis (remember erect penis is antatomical view) so top of penis when flaccid is gone **commonly seen with ectopic vesicae

Question 41

Suprarenal glands have three different parts including the medulla, capsule and cortex. The cortex is derived from?

Answer 41

coelomic epithelium (somatic mesoderm layer of lateral plate)

Question 42

How is the cortex formed?

Answer 42

coelomic epithelium forms a fetal cortex which is a cellular wave during week 6

Question 43

The medulla is formed from nueral crest cells which migrate to?

Answer 43

the fetal cortex chromaffin system/cells which give rise to medulla

Question 44

There is then a second wave of ceolomic epithelium in the cortex which forms the ?

Answer 44

adult/definitive cortex

Question 45

The capsule surrounding the kidneyy comes from?

Answer 45

mesonephric mesoderm (intermediate mesoderm)

Question 46

The fetal cortex is a source of a variety of hormones including _____ (2) and dihydroepiandrosterone (estrogen precursor) which is needed for placental development and pregnancy

Answer 46

pituitary ACTH and glucocorticoids