Urogenital system embryology Flashcards
Which structure gives rise to the urinary system?
Where does it develop from?
nephrogenic cord
develops from urogenital ridge (intermediate mesoderm)
1 - 5
Another name for #4.
1) liver primordium
2) pronephros
3) nephrogenic cord
4) mesonephric duct (WOLFFIAN)
5) mesonephric tubules
6 - 11
6) ureteric bud
7) cloaca
8) allantois
9) omphalomesenteric duct
10) mesonephros
11) metanephros
1 - 5
Another name for #5.
1) intraembryonic coelom
2) extraembryonic coelom
3) yolk sac
4) midgut
5) mesonephric duct (WOLFFIAN)
6 - 11
6) nephrogenic cord
7) urogenital ridge
8) dorsal aorta
9) notochord
10) neural tube
11) dev. spinal ganglion
What are the 3 primordial kidney sets?
Give some brief information.
In which segments of the vertebral column are they located?
pronephroi C6 - Th2
- transitory, non-functional
- pronephric duct opens into cloaca
mesonephroi Th2 - L3
- functional, interim kidneys
- consist of glomeruli + mesonephric tubules
- pronephric duct becomes mesonephric duct
metaneprohoi L3 - L5
- delevop from ureteric bud + metanephrogenic blastema
- form adult kidneys, ureter
How do kidneys/ureters develop?
Acronym?
- *P** M Se B Bl
- *U** T Ne A
- Pronephroi + pronephric duct develop
- Mesonephroi develop, take over pronephric duct
- urine Secretion starts into amnion as nephrons are developed
- ureteric Bud develops from mesonephric duct
- metanephrogenic Blastema develops from caudal part of nephrogenic cord
- stalk of ureteric bud becomes Ureter
- collecting Tubules form from ureteric bud
- Nephrons develop from ureteric bud + metanephrogenic blastema
- Ascent of kidneys
1 - 5
Another name for #1.
1) mesonephric duct (WOLFFIAN)
2) stalk of ureteric bud
3) ureteric bud
4) metanephrogenic blastema
5) ureter
6 - 10
6) major calyx
7) renal pelvis
8) minor calyx
9) ureter
10) lobe of kidney
11 - 13
What do #11 eventually form?
11) mesenchymal cell clusters → metanephric vesicles
12) straight collecting tubule
13) arched collecting tubule
1 - 5
Another name for #4.
Which structures are eventually formed by #5?
4, #5 could also be mesonephric …, but here we are talking abt the development of
1) dorsal aorta
2) urogenital ridge
3) metanephric vesicle
4) mesonephric duct (WOLFFIAN)
5) metanephric tubule → prox./dist. convoluted tubule + loop of HENLE
nephrons in the permanent kidney,
thus metanephros
6 - 10
6) afferent glomerular vessel
7) glomerulus
8) dev. Bowman’s capsule
9) afferent + efferent glomerular vessels
10) primordium of gonad (testis/ovary)
#4, #5 could also be mesonephric …, but here we are talking abt the development of nephrons in the permanent kidney, thus metanephros
What happens to the lobes of the kidney (cf. development of permanent kidney)?
disappear at age 1
What is reciprocal induction?
ureteric bud induces development of nephrons from metanephrogenic blatesma
metanephrogenic blatesma induces branching of ureteric bud
What is the reason for the ascent of the kidneys?
When does it stop?
What are its consequences?
caudal growth of embryos body → ascent → stops when kidneys come in contact with suprarenal glands
consequences:
- hilum comes to lie in final position
- initially supplied by a. iliaca communis
- finally supplied by aorta pars abdominalis
How does the urinary bladder develop?
- allantois constricts → urachus
- vesical part of urogenital sinus enlarges
- mesonephric ducts (ureters) are incorporated as trigonum vesicae
What is the remnant of the urachus?
lig. umbilicale medianum
1 - 5
Another name for #5.
the yellow indicated ureter should actually be purple since it derives from the Wolffian duct
1) vesical part of UG sinus
2) pelvic part of UG sinus
3) phallic part of UG sinus
4) urogenital sinus
5) mesonephric duct (WOLFFIAN)
6 - 10
the yellow indicated ureter should actually be purple since it derives from the Wolffian duct
6) ureteric bud
7) urorectal septum
8) cloacal membrane
9) rectum
10) genital tubercle
11 - 15
the yellow indicated ureter should actually be purple since it derives from the Wolffian duct
11) urachus
12) kidney
13) uterine tube
14) ovary
15) vas deferens
16 - 20
the yellow indicated ureter should actually be purple since it derives from the Wolffian duct
16) testis
17) vagina
18) clitoris
19) penis
20) spongy urethra
21 - 23
the yellow indicated ureter should actually be purple since it derives from the Wolffian duct
21) urethra
22) urinary bladder
23) uterus
How does the location of the urinary bladder change after birth?
orginally in the abdomen → enters greater pelvis (∽ 6y) → enters lesser pelvis (∽ puberty)
Where does the urethra develop from?
Differentiate btw male/female.
- female: entire epithelium of urethra from urogenital sinus
-
male: epithelium of urethra from urogenital sinus btw urethral folds
BUT: in glans from surface ectoderm
⇒ both: conn. tissue/mm. from surr. splanchnic mesenchyme
explains transition of urothelium to pseudostrat. col. to str. squ. non-ker. (only in males!!)
1 - 6
Where does #1 originate from?
Another name for #5 and #6.
1) primordial germ cells (originate from dorsal mesentery)
2) gut tube
3) gonadal ridge
4) mesonephric tubule
5) mesonephric duct (WOLFFIAN)
6) paramesonephric duct (MÜLLERIAN)
here #4 could NOT be meta… instead of meso…, because the development of the gonadal ridge is restricted to the region where the mesonephros grows
7 - 12
7) aorta
8) dorsal mesentery
9) urogenital ridge
10) gonadal cord
11) medulla of gonad
12) cortex of gonad
How do indifferent gonads develop?
When do they start to differentiate into testes/ovaries?
What does it mean?
indifferent until end of week 6 = identical in appearance (both sexes)
- growing mesonephros produces gonadal ridge in urogenital ridge
- gonadal cords grow → cortex/medulla of gonad
- primordial germ cells from dorsal mes. migrate + are incorporated into gonadal cords
-
in week 7: sexual differentiation depends on
- testis-determining factor TDF → male
- no TDF → female
1 - 5
Another name for #3 and #4.
1) gut tube
2) mesonephric vesicle
3) mesonephric tube (WOLFFIAN)
4) paramesonephric tube (MÜLLERIAN)
5) primordial germ cells
6 - 10
6) seminiferous cords
7) mesorchium
8) rete testis
9) septum of testis
10) tunica albuginea
List the hormones and cells that are responsible for masculine differentiation (besides TDF).
human chorionic gonadotropin hCG induces
- LEYDIG cells → testosterone⇒ stimulate WOLFFIAN duct to form male genital ducts
-
Sertoli cells → anti-müllerian hormone (AMH)
⇒ stimulates MÜLLERIAN ducts to regress
How do testes develop?
all events induced by TDF
- gonadal cords (now seminiferous cords) pinch off to form rete testis
- tunica albuginea forms
- testis seperate from degenerating mesonephros → suspended by mesorchium
- seminiferous cords become seminiferous tubules
- mesenchyme btw tubules → Leydig cells
- seminiferous tubules → Sertoli cells
- surface epithelium of testes flattens → tunica vaginalis testis
- rete testis and mesonephric tubules fuse → efferent ductules
1 - 6
Another name for #5.
1) gut tube
2) cortical cords
3) former gonadal cords
4) rete ovarii
5) paramesonephric duct (MÜLLERIAN)
6) mesovarium
7 - 12
Another name for #9 and #12.
7) surface epithelium
8) prim. germ cells
9) mesonephric duct (WOLFFIAN) + vesicle
10) degenerating rete ovarii
11) uterine tube
12) prim. ovarian follicles (= oogonia)
How do the ovaries develop?
all events induced by absence of TDF
- ovary seperate degenerating mesonephros → suspended by mesovarium
- gonadal cords seperate → rete ovarii
- cortical cords form from mesothelium of peritoneum
- primordial germ cells incorporated into cortical cords
- cortical cords containing a germ cell break up → form primordial follicle (= oogonium) → active mitosis of oogonia → become primary oocytes after birth
- surface epithelium flattens → forms tunica albuginea that seperates follicles from cortex
Where do the MÜLLERIAN ducts develop from?
Which transitional structures are formed by them in females?
develop from mesothelium lateral to mesonephroi
open from peritoneal cavity into future pelvic region
in females: fuse caudally → form uterovaginal primordium
→ produces sinus tubercle on urogenital sinus
How do epididymis and its accompanied structures develop?
-
distal end of Wolffian duct
- appendix edididymis
- convolutes → epididymis
- vas deferens when invested w/ sm. m.
- ductus ejaculatorius
-
mesonephric tubules (originally from metan. blastema)
- efferent tubules
- paradidymis
Where does the uterus develop from?
uterovaginal primordium + surr. splanchnic mesenchyme (→ endometrial stroma + myometrium)
Which structures form lig. latum?
Which other structures are formed during that proc.?
fusion of MÜLLERIAN ducts
→ lig. latum + mesenchyme proliferates → parametrium
Where do accessory sex glands in males and females develop from?
mostly derived from endoderm of UG sinus at parts of urethra
male:
- prost. part of urethra → prostate
- spongy part of urethra → Cowper gll.
- BUT: Wolffian duct → gl. vesiculosa
females:
- urethral + paraurethral gll.
- maj. vestibular gll.
How does the vagina develop?
- sinus tubercle forms laterally sinovaginal bulbs
- sinovaginal bulbs fuse → vaginal plate
- central parts break down → lumen
→ hymen develops as only remnant of sinus tubercle
Describe the indifferent part of the development of external genetalia.
mesenchyme produces genital tubercle
- *→ labioscrotal folds** (lateral)
- *→ urethral folds** (medial), surround UG sinus
How do the male external genetalia develop?
- as genital tubercle elongates → phallus
- urethral folds approach each other → spongy urethra
- at glans penis ectodermal ingrowth meets spongy urethra → external urethral orifice formed
- ectoderm around glans → preputium
- corpora cav./spong. formed by mesenchyme
- labioscrotal folds fuse → scrotum + raphe scroti
How do the female external genetalia develop?
- instead of phallus clitoris formed from genital tubercle
-
urethral folds
- fuse posteriorly → frenulum of labia majora
- unfused → labia minora
-
labioscrotal folds
- fuse post./ant. → labial commissurae + mons pubis
- unfused → labia majora
What is the gubernaculum, what does it do and what are its derivatives?
outgrowth from caudal pole of gonad into labioscrotal folds
→ forms path for processus vaginalis → inguinal canal
derivatives:
- in males: gubernaculum testis
- in females: lig. ovarii prop., lig. teres uteri
What are the deep and superficial inguinal ring?
openings produced by gubernaculum
- deep: in transversalis fascia
- superficial: in external oblique aponeurosis
What are causes and consequences of the descent of the testes?
causes:
- growing pelvis + deg. mesonephroi
- increased intraabdominal pressure due to growing abd. viscera
consequences:
- ureter crossing w/ ductus deferens
- course of test. vessels
- coats of testes
In what way does the descent of the ovaries differ from that of testes?
do not pass from pelvis to enter inguinal canal
proc. vaginalis disappears, BUT sometimes persistent as canal of NUCK
What are the derivatives of the Wolffian duct in males?
- appendix + duct of epididymis
- ductus deferens
- ejaculatory duct + seminal gland
in both:
- ureter + trigonum vesicae
- renal pelvis, calices + collecting tubules
What are the derivatives of the Wolffian duct in females?
- appendix vesiculosa
- duct of epophoron
- longitudinal duct; Gartner duct
in both:
- ureter + trigonum vesicae
- renal pelvis, calices + collecting tubules
What are the derivatives of the Müllerian duct in males?
- appendix of testis
What are the derivatives of the Müllerian duct in females?
- hydatid of Morgangni (= paratubal cyst at infundibulum of uterine tube)
- uterine tube
- uterus
What are the derivatives of the mesonephric tubules in males/females?
male:
- efferent ductules of testis
- paradidymis
female:
- epoophoron (like paraophoron, but more cranial)
- paraophoron (btw ovary + uterus)
