Embryology urogenital system

Question 1

Urogenital system develops from ?

Answer 1

intermediate mesenchyme, from dorsal body wall of embryo

Question 2

3 sets of kidneys in embryo?

Answer 2

pronephroi
mesonephroi
metanephroi

Question 3

pronephroi

Answer 3

early in 4th week

few cell clusters + tubular structure opening into cloaca

Question 4

mesonephroi

Answer 4

late in 4th week, caudal to pronephroi, functions 4 weeks
have glomeruli and tubules
tubules open into mesonephric ducts, ducts into cloaca

Question 5

metanephroi

Answer 5

in 5th week, functional 4 weeks later

urine into amniotic cavity, component amniotic fluid

Question 6

kidneys develop from which 2 structures? What develops from these structures?

Answer 6

ureteric bud (metanephric diverticulum) = outgrowth mesonephric duct near cloaca --> cranial part becomes collecting tubules
stalk ureteric bud becomes ureter
metanephrogenic blastema (mass of mesenchyme) = from caudal part nephrogenic cord

Question 7

How does the position of the kidneys change?

Answer 7

Kidneys ascend due to caudal growing embryo

Hilum initially faces ventral –> rotates medially, ending up anteromedially

Question 8

How does the blood supply to kidneys change?

Answer 8

During changes in position the kidneys receive blood from vessels closed by

Question 9

Renal agenesis (abscence) develops how? types?

Answer 9

Develops when ureteric buds do not develop or primordia of ureters degenerate
failure of buds to penetrate blastema cause no nephrons to develop
unilateral –> males, left absent, compensatory
bilateral –> incompatible with life (Potter syndrome)

Question 10

Malrotation of kidney forms?

Answer 10

Failure to rotate –> hilum anteriorly
Hilum posteriorly = rotation too far
hilum laterally = rotation lateral instead of medial

Question 11

Ectopic kidneys

Answer 11

1 or both kidneys are in abnormal position, associated with malrotation –> supplied by several vessels
pelvic kidneys closer, usually fuse to form discoid (pancake kidney)

Question 12

Crossed renal ectopia

Answer 12

kidney crosses to other side, 90% fuse

Question 13

Unilateral fused kidney

Answer 13

kidneys fuse after leaving pelvis, 1 kidney atains normal position taking other kidney with it

Question 14

Horseshoe kidney

Answer 14

poles of kidney are fused, usually inferior
lies in pubic region, no symptoms
Associated with Turner’s syndrome

Question 15

Duplication urinary tract: how does it result ?

Answer 15

abnormal division of ureteric bud

Question 16

Duplication of urinary tract types?

Answer 16

Incomplete division = divided kidney with bifid ureter
complete division = double kidney with bifid ureter or separated ureters
supernumerary (extra) kidney with its own ureter –> from formation 2 ureteric buds

Question 17

Ectopic ureter

Answer 17

does not enter bladder
males = ureter will open into neck bladder or prostatic part urethra
females = ureter opens into neck bladder or urethra or vagina

Question 18

Cystic kidney disease autosomal recessive polycystic type ?

Answer 18

both kidneys contain many small cysts, renal insufficiency

Question 19

cystic kidney disease multicystic dysplastic kidney type ?

Answer 19

dysmorphology, abnormal development renal system, often unilateral, fewer cysts than in autosomal

Question 20

Urogenital sinus divided into which 3 parts?

Answer 20

Vesical part = forms most bladder
Pelvic part = urethra, prostatic part males
Phallic part = grows toward genital tubercle = primordium penis or clitoris

Question 21

Urachus in adults is?

Answer 21

median umbilical ligament

Question 22

What is the urachus?

Answer 22

the allontois that is constricted and becomes thick fibrous cord, extending from apex of bladder to umbilicus.

Question 23

What happens as the bladder enlarges?

Answer 23

distal parts mesonephric ducts incorporated in dorsal wall bladder –> ducts absorbed form opening ureters