Development of the urogenital system

Question 1

what does the paraxial mesoderm form?

Answer 1

forms the somites + vertebral column

Question 2

what does the lateral plate mesoderm form?

Answer 2

forms the body walls

Question 3

what does the intermediate mesoderm form?

Answer 3

forms the urogenital system

Question 4

early proliferation of the intermediate mesoderm causes?

Answer 4

longitudinal swelling - urogenital ridge/plate

Question 5

what does the intermediate mesoderm consist of?

Answer 5

laterally-positioned nephrogenic cord (forms kidneys & ureter)
and a medially positioned gonadal ridge (for ovary/testis & female/male genital tract formation

Question 6

what does the nephrogenic cord undergo?

Answer 6

undergoes segmentation

Question 7

the pronenphros and mesonephros develop similarly - how?

Answer 7

the nephrogenic cord undergoes segmentation, segments become tubules, tubules drain into a duct & eventually tubules disintegrate

Question 8

intermediate mesoderm for free swimming larvae?

Answer 8

pronephros

Question 9

intermediate mesoderm for fish and amphibians?

Answer 9

mesonephros

Question 10

intermediate mesoderm for mammals, reptiles and birds?

Answer 10

metanephros

Question 11

metanephros originate from?

Answer 11

two sources:
Ureteric bud
Metanephrongenic mass

Question 12

ureteric bud?

Answer 12

grows out of the mesonephric duct - bud eventually develops into the ureter, renal pelvis and collecting ducts

Question 13

metanephrogenic mass?

Answer 13

caudal region of the nephrongenic cord; mass forms the nephrons

Question 14

nephron formation: cells next to metanephrogenic mass…

Answer 14

grow and form cell cords

Question 15

during nephron formation, what happens to the cords?

Answer 15

they canalise and elongate becoming S-shaped metanephric tubules

Question 16

what does the end of the metanephric tubule do during nephron formation?

Answer 16

the end of metanephric tubule expands to surround a capillary glomerulus
other end must meet the collecting tubule

Question 17

during development of the hindgut - what happens to the cloaca?

Answer 17

it is subdivided by the Urorectal septum

Question 18

what does the urorectal septum divide the cloaca into?

Answer 18

dorsally: rectum, anal canal and anal membrane
ventrally: urogenital sinus and urogenital membrane

Question 19

membranes of the cloaca degenerate to form?

Answer 19

the anal and urogenital orifice

Question 20

cranially the urogenital sinus connects with?

Answer 20

the urachus

Question 21

what is the trigona region?

Answer 21

it is a triangular region located in the dorsal wall of the bladder neck

Question 22

what is the trigona region formed by?

Answer 22

by longitudinal smooth muscle from the ureters, serves to anchor ureters to the bladder neck and urethra

Question 23

where is the trigona region?

Answer 23

it is a differential growth of the dorsal wall of the bladder

Question 24

what does the trigona region represent?

Answer 24

represents mesonephric duct and later ureter openings and finally being switched

Question 25

base of this trigona is...

Answer 25

an entrance of forming ureters and apex is where mesonephric ducts enter

Question 26

what is hydronephrosis?

Answer 26

abnormalities of the urinary development (cystic or polycystic kidneys) ureteric atresia or failure of nephrons to communicate with collecting tubules

Question 27

abnormalities of the urinary development?

Answer 27

patent urachus (allantoic stalk fails to close) ectopic ureter (ureter opens into the urethra or vagina)

Question 28

what indifferent gonads do both sexes have?

Answer 28

both sexes have male (mesonephric) and female (paramesonephric) genital ducts and a urogenital sinus

Question 29

what duct persists after the mesonephros disintergrates?

Answer 29

mesonephric (Wolffian) duct

Question 30

what duct develops along the surface of the mesonephros?

Answer 30

Paramesonephric (Mullerian) duct

Question 31

What does a gonad contain?

Answer 31

germ cells and supporting cells

Question 32

supporting cells form?

Answer 32

form cellular cords (gonadal cords)

Question 33

germ cells proliferate and migrate...?

Answer 33

inside gonadal cords so that they are surrounded by supporting cells

Question 34

germ cells migration induces?

Answer 34

induces further gonadal development

Question 35

what do germ cells depend on for their survival?

Answer 35

on supporting cells

Question 36

for the male - gonadal cords hypertrophy is called?

Answer 36

seminiferous cords

Question 37

germ cells within the seminiferous cords become what in males?

Answer 37

become spermatogonia

Question 38

at puberty in males, what happens to the cords?

Answer 38

they canalise - become tubules and spermatogonia initiate spermatogenesis

Question 39

cord cells that lack germ cells become? in males -

Answer 39

they become tubules of the rete testis

Question 40

for development of the testis - supporting cells differentiate into?

Answer 40

into sustentacular (Sertoli) cells and interstitial cells (Leydig cells)

Question 41

where are sustentacular cells located?

Answer 41

in the walls of seminiferous tubes

Question 42

what do sustentacular cells do during development of the testis?

Answer 42

secrete inhibitory factors that suppress both spermatogenesis and female duct development

Question 43

interstitial cells located outside of seminiferous tubules become two populations: what do they each do?

Answer 43

one produces androgen hormones immediately the other population delays androgen production until sexual maturity

Question 44

during development of ovary - the gonadal cords do what?

Answer 44

they reorganise so that individual germ cells surrounds by supporting cells - primordial follicles are formed

Question 45

during development of ovary - what happens to germ cells (oogonia)?

Answer 45

differentiate into primary oocytes (lifetime supply is present in the neonatal ovary)

Question 46

mesonephric duct in absence of testosterone?

Answer 46

it fails to develop

Question 47

what becomes uterine tube?

Answer 47

the cranial part of paramesonephric duct remains open and becomes uterine tube

Question 48

larger body because fusion is stronger of the paramesonephric duct

Question 49

caudal part of paramesonephric duct becomes?

Answer 49

becomes uterine horn

Question 50

what happens more caudally to the paramesonephric duct becoming the uterine horn?

Answer 50

bilateral paramesonephric duct shift medially and fuse into a single tube-fused ducts become uterine body, uterine cervix and cranial vagina

Question 51

external genitalia for females is derived from?

Answer 51

from three different perineal swellings

Question 52

what are the three perineal swellings that the external genitalia are derived from?

Answer 52

bilateral urogenital folds a genital tubercle bilateral genital

Question 53

bilateral urogenital folds?

Answer 53

border the urogenital orifice and elongate ventrally

Question 54

a genital tubercle?

Answer 54

develops at the ventral commissure of the urogenital folds

Question 55

bilateral genital?

Answer 55

(labioscrotal) swellings are located lateral to the urogenital swellings (in domestic mammals these persist only in males)

Question 56

the mesonephros is the functional kidney for which animal?

Answer 56

fish

Question 57

metanephric kidney develop from which region?

Answer 57

pelvic

Question 58

during development which structure becomes ureter, renal pelvis and collecting ducts?

Answer 58

ureteric bud

Question 59

what is being switched in the TRIGONA region?

Answer 59

mesonephric duct and ureter openings are being switched ALSO ureteric bud grows out of the mesonephric duct ureters migrate cranially

Question 60

trigone of the bladder developed from?

Answer 60

urogenital sinus

Question 61

mesonephric duct become ductus epididymis and the ducts deferences T/F?

Answer 61

true

Question 62

Without testosterone - the mesonephric ducts will regress T/F?

Answer 62

true

Question 63

What is the other name for sustentacular cells?

Answer 63

sertoli cells