dev of urnary system

Question 1

What is the origin of the cells forming the kidney and ureters

Answer 1

kidneys and ureters are derived from intermediate mesoderm (IM)- visible during week 3, IM separates from paraxial mesoderm during lateral folding

Urogenital Ridge (urinary and reproductive components share common precursors)

reliant upon Pax 2, 8 and Lim 1

Question 2

What is the origin of the cells forming the lining of the bladder and urethra

Answer 2

epithelial lining is derived from endoderm (that lines terminal end of hindgut)– cloaca

Wall of bladder and urethra, smooth muscle and CT - from splanchnic mesoderm

Question 3

What becomes of the mesonephric duct and tubules

Answer 3

the duct and tubules develop within the thoracic and lumbar portions of notochord– mesonephric kidney

duct is mesonephric/wolffian duct

mesonephric duct induces formation of a series of tubules/primitive nephrons–empty into duct, these are mesonephric tubules

Question 4

metanephric diverticulum and metanephrogenic mesenchyme

Answer 4

metenephric diverticulum/ ureteric bud and metanephrogenic mesenchyme derived from im

become kidney appear during week 5

failure of m. diverticulum to form–> renal agenesis

Question 5

What is the importance of the ampulla of the metanephric diverticulum, how does it affect the metanephrogenic mesenchyme

Answer 5

Expression of GDNF (glial derived neutrophic factor) and retinoic acid by the mesenchyme induce the formation of the MD, distal MD becomes dilated and is called the AMPULLA– gives signals for development of the nephron

Question 6

How is the metanephrogenic mesenchyme converted into a nephron

Answer 6

inductive signals from ampulla of md mediate differentiation of a subset of MM into a nephron– segregation, condensation around ampulla, mesenchyme to epithelium transformation forming an epithelial lined vesicle, becomes S shaped tubule

urine begins to form at wk 10- 12

Question 7

how does the nephron become vascularized

Answer 7

metanephrogenic mesenchyme thats been induced by signals from the MD secretes angiogenic factors (VEGF)`

Question 8

How do the pelvis ureters and calyces of the kidney form

Answer 8

The pelvis, ureters, calyces and collecting tubules formby branching of the MD

New nephrons are not formed after birth, once ampulla is gone, no more nephron formation

Question 9

How is the Cloaca subdivided

Answer 9

The cloaca is the dilated terminal portion of the hindgut at the caudal end of the embryo

Your anus+ pee hole

during week 5, a wedge of mesenchyme, the urorectal septum begins to divide to a primary urogenital sinus and anorectal canal

The Cranial portion of the UG sinus becomes the epithelial lining of the UBladder

Question 10

Trigone

Answer 10

thickend tiangle of internally posterior wall of the bladder

Where the ureters enter and where the urethra leaves

Males the mesonephric ducts open into the forming prostatic urethra

Question 11

Urachus/allantois

Answer 11

a cyst may occur anywhere along the median umbilical ligament

Question 12

Renal agenesis

Answer 12

unilateral (usually asymptomatic, 30-40 have associated anomalies, left kidney is most often absent)

Bilateral- incompatible with life, severe oligohydramnios, pulm hypoplasia, potters facial sequence

Question 13

Renal dysplasia

Answer 13

Cysts and primitive ducts form resulting in a nonfunctional kidney, fatal if bilateral,

Question 14

renal hypoplasia

Answer 14

kidneys may be small but may be functional

Question 15

Ectopic kidney

Answer 15

pelvic kidney usually left sided due to failure to ascent, crossed renal ectopia,

Question 16

Horseshoe kidney

Answer 16

Inferior poles fuse

Question 17

Polycystic kidney disease

Answer 17

autosomal rececssive type- enlarged kidneys with cortical cyst, reniform shape is maintained, in newborns its usually fatal, in kids (liver HTN CHF), in adults ( liver fibrosis, potal HTN)

Dominant type: bilateral cystic kidneys with large cysts, symptoms in 30s and 40s HTN, berry aneurysms, intestinal diverticulosis

Question 18

Exstrophy of bladder

Answer 18

common in males, interior bladder is exposed to the exterior, due to weakening of the ventral abdominal wall that causes it ot rupture during development, exposing the inferior of the bladder, associated epispadus in males as well as UG and skeletal anomalies

Question 19

Posterior urethral valves

Answer 19

Only in males, tissue folds of the posterior urethra mucosa

blocks the urethra

rnal failure in kids

Question 20

Nephroblastoma

Answer 20

One of two common neoplasms in kids, later in cortex, associated withwt 1 gene located

Question 21

Hydronephrosis

Answer 21

Distension of the renal pelvis and calices due to obstruction of urinary flow

Question 22

Urethral agenesis

Answer 22

associated with obstruction of urinary flow from bladder, prune belly

Question 23

anomalies of the ureter

Answer 23

duplication, primary reflux, ureterocele, megaureter, ectopic ureter