Development of urogenital system

1. Development of kidney and ureter

2. Development of urinary bladder and

urethra

3. Abnormality in urinary system

4. Development of gonad

5. Development of reproductive tracts

6. Abnormality in reproductive system

Intermediate m

esoderm

Primordium of urogenital syste

m

Intermediate mesoderm ─────→

Nephrogenic cord

───→ Urogenital

ridge3rd week

───

Mesoneohric ridge

Gonadal ridge

Urinary system,

genital excurrent duts

Gonad

Intermediate mesoderm

Urogenital ridge

Head (segmentation)→ Nephrotome →Pronephros

Other (migration, proliferation)→ Nephrogenic cord → Mesonephros and Metanephros

Gonadal ridge

Mesonephric ridge

Mesonephric ridge

Gonadal ridge

Nephrotome (7-14th somite)

Pronephric tubule

Pronephric duct

Degeneration in 1 week

Mesonephric duct

Pronephric

tubule

Pronephric

duct

Development of kidney and ureter

1. Pronephros 4th week, no function

2. Mesonephros

14-18th somite

Time ： end of 4th week

Function:

transient urinary

Destiny:

Most degeneration,

Small part form male

excurrent duct

Mesonephric duct

Mesonephric tubule

Mesonephric duct

Middle part of nephrogenic cord

Mesonephric tubule

Inner part form renal capsule

End bind to colaca

80 transverse S-shaped tubule

Continus to pronephric duct

Outer end bind to mesonephric duct

3.Metanephros Source one: Ureteric bud Source two: Metanephrogenic blastema Time ： begin at 5th week, exist forever Function ： begin at 3th month, urinary function Position ： rise gradually

Mesonephric duct

Mesonephric tubule

Metanephros

Ureteric bud

End of mesonephri

c duct (adjacent to colaca)

Ureter

Renal pelvis, renal calyce

Collecting tube

Prolong

Enbranchment＞ 12

(The end branched as T)

Source one

Cap-shaped cell cluster

Metanephrogenic blastema

(Mesoderm of the mesonephric ridge)

S-shaped tubule

Connect with colle

cting tubule

Renal t

ubule

Renal caps

ule Glomerulus

Source two

Renal corpuscle

Nephron＋

Metanephric tubule

Mesonephric tubule

Ureteric bud

Metanephrogenic blastema

Renal pelvis

Collecting tubule

Renal calyce

From its original location (adjacent to the developing baldder) to its

mature location (in the retroperitoneum just caudal to the diaphrag

m)

Colaca4-7th week

Ureorectal septum

Urogenital sinus

Anorectal canal

Upper part

Middle part

Lower part

Male Female

Urinary bladder

Upper part of urethra

Lower part of urethra

Urinary bladder

Urethra

Vestibula of vagina

Development of urinary bladder and urethra

A B

C D E

Ureter Mesonephric duct

Abnormality in urinary system

1. Polycystic kidney 2. Horseshoe kidney

3. Single kidney

Right single kidney Left single kidney

4. Double ureter 5. Ectopic kidney

6. Urachal fistula 7. Exstrophy of bladder

Development of gonad

Gonad differentiation at 7th week

Developmental stage： Sex undifferentiated stage → Sex differentiated stage

Reproductive tracts ：２ → 1

Proper current ： → Feamle

Testis determining factor, TDF

TDF determine the differentiation to testis.

The gene of TDF located at sex determining region of the Y (SRY).

1. Development of

undifferentiated gonad

Gonadal ridge 6th week

Primitive s

ex cord Superfacail epithelium →cell cord

Endoderm cell of yolk sac

3rd to 4th week

Proliferation differentiation

Promordial germ cells

6th weekMigration in 1 week

Large and round endoderm cells in yolk sac

Promordial germ cells

Migration of promordial germ cells

Dorsal mesentary of the gut

2. Development of testis

Primary sex cord (TDF)

Mesenchymal cells

Interstitial cells

Cells of sex cord Promordial germ cells

Sustantacular cells Spermatogonium ＋

＋ Testis

Seminiferous tubule

Seperated from surface 7th week

3. Development of ovary

Mesenchymal cells

Stroma

Cells of sex cord Primordial germ cells

Follicular cells Ooginum＋ ＋ Ovary

Secondary sex cord (Cortical cord ）

Primordial follicel

16th week

After 8 weeks

Primary sex cord

Degeneration

Superfacial epithelium No TDF

Testis Rete testis

Tubule rectus

Seminiferous tubule

Follicle

Ovary

Spermatogonium

Sustantacular cell

Seminiferous tubule Follicle

Primary oocyte

Follicular cell

４ . Descend of testis and ovary

Development of reproductive tracts

1. Undifferentiated stage

2. Differentiation of male reproductive tract

Mesonephric tubule

Most of ── degeneration

Some of ── efferent ducts

Mesonephric duct

Proximal part ── epididymal duct

Distal part── ductus deferens and ejaculatory duct

Paramesonephric duct

Regression──

3. Differentiation of female reproductive tract

Paramesonephric d

uct

Upper and middle segment ： oviduct

Lower segment: uterus

regressionMesonephric duct and tubule

Sinus tubercle ：Vaginal plate Vagina

Abnormality of reproductive system

1. Cryptorchidism

2. Congenital inguinal hernia

3. Double uterus

4. Vaginal atresia

5. Hypospadias

6. Hermaphroditism