Urogenital system

1. Urogenital system 陳建榮 http://web.nchu.edu.tw/pweb/users/chenjr/

2. Development of Urogenital System Adrenal Glands Kidneys The development of the kidneys from the pronephros to their ascent to the level of L1. Reproductive System The development of male and female genitalia from the partitioning of the cloaca to the final differentiated state.

3. Embryology of the urogenital system -Urinary system • Genital system Urogenital ridge (intermediate mesoderm) along the posterior abdominal wall -- urinary system  nephrogenic cord生腎索 -- genital system  gonadal ridge生殖脊 Kidney develops first (functional; reproductive later)

4. Urinary system Genital system

5. Normal Development of the Adrenal Glands Formation of the adrenal cortex The adrenal glands is derived from the intermediate mesoderm. The adrenal glands have two developmentally distinct parts: the medulla and the cortex. Formation of the adrenal medulla Development of zones of adrenal gland

6. 球小帶 (Aldosterone ) 束狀帶 (Glucocorticoids ) 網狀帶 (DHEA)

7. 6th weeks

8. Normal Development of the Adrenal Glands Formation of the adrenal cortex Formation of the adrenal medulla Neural crest cells migrate into the center of this aggregate to develop the adrenal medulla. The cells differentiate into sympathetic nerve cells and show evidence of catecholamine production in 10th week of fetal life. Development of zones of adrenal gland

10. Normal Development of the Adrenal Glands Formation of the adrenal cortex Formation of the adrenal medulla Development of zones of adrenal gland • During fetal period • zona glomerulus球小帶 • zona fasciculata束狀帶 • 3 years old • zona reticularis網狀帶forms • The fetal adrenal glands are larger than the fetal kidney at four months. Even at birth they are relatively quite large (about 20 times their relative size in the adult). • After birth, the fetal cortex rapidly undergoes regression.

11. 2 1 3

12. Congenital adrenal hyperplasia (CAH) 先天性腎上腺增生症

13. Normal Development of the Urinary System Development of kidney Early kidney development (pronephros) Development of mesonephros Development of metanephrosAscent of the kidneys Development of the Urinary Bladder

14. Normal Development of theKidneys Pronephros:原腎(4th week, nonfunctional) • mesenchymal cell aggregates in neck region of embryo, and soon transformed into ligament • pronephros attached to pronephric ducts原腎管 • promesonephric ducts used in next stage of kidney development, these ducts end in the cloacal region caudal to the mesenchymal cell aggregates of the pronephros. Mesonephros: Metanephros:

16. Normal Development of the Kidneys Pronephros: (4th week, nonfunctional) Mesonephros: 中腎(functional) • mesonephros begins development late in 4th week lie caudal to pronephros • mesonephros consists of glomeruli and mesonephric tubules中腎小管 which open into mesonephric duct, a continuation of the pronephric duct mesonephric duct opens into cloaca • mesonephros proper degenerates but tubules and ducts have derivatives in adult males (tubules form ductuli efferentes輸出小管 and ducts form a number of reproductive structures to be discussed later). Metanephros:

19. Development of the Metanephros後腎: • The ureteric bud forms from an outgrowth of the mesonephric duct near the cloaca. The ureter, renal pelvis, major and minor calyces, collecting ducts and collecting tubules are all formed from the ureteric bud. • The metanephric mesenchyme forms from the caudal portion of the intermediate mass, and it surrounds the end of the ureteric bud. • As the kidney grows the ureteric bud forms finger-like projections. • The first 4 generations of the projections form the major calyx, the next 2 generations form the minor calyces, and the remaining projections form the straight and arched collecting tubules.

22. 腎盂

23. Normal development of Nephrons • The arched collecting tubules induce growth of the surrounding mesenchyme, which forms a tubule in the metanephric mass後腎原基 of mesoderm. • These tubules form the parts of the nephron: glomerulus, Bowman's capsule, convoluted tubule, loop of Henle. • Formation of the nephrons of the permanent kidney begins at 8th week. • The metanephric vesicles elongate to form tubules which directly contact the arched collecting tubules. • The metanephric tubules are lobulated and remain this way until after birth.

26. Normal Development of the Urinary System Development of kidney Early kidney development (pronephros) Development of mesonephros Development of metanephros Ascent of the kidneys Development of the Urinary Bladder

27. Ascent of the kidneys • During the 5th and 6th weeks of development, the mature kidneys lie in the pelvis with their hila pointed anteriorly. • As the pelvis and abdomen grow, the kidneys slowly move upward. • By the 7th week, the hilum points medially and the kidneys are located in the abdomen. • As the embryo continues to grow in a caudal direction, the kidneys come to lie in a retroperitoneal position at the level of L1 by the 9th week of development.

28. Clinical problems Accessory renal arteries

30. Renal agenesis Bilateral renal agenesis Malrotated kidney Ectopic kidney Duplication of urinary tract Ectopic ureter

31. Duplication of urinary tract

32. Horseshoe kidney

33. Development of Urinary Bladder • Cloaca (uro-rectal septum尿生殖隔) • urogenital sinus泌尿生殖竇 • Anorectal canal肛門生殖管 • The uro-genital sinus may be divided into three component parts. • The cranial portion which is continuous with the allantois and forms the bladder proper. • The pelvic part of the sinus forms the prostatic urethra and epithelium as well as the membranous urethra and bulbo urethral glands in the male and the membranous urethra and part of the vagina in females. • The caudal portion, or definitive uro-genital sinus, forms the penile urethra in males and the vestibule in females.

34. The trigone portion is formed by the caudal ends of the mesonephric ducts. • The mesonephric ducts begin to become incorporated into the wall of the bladder dragging the ureters along with them. • The mesonephric ducts enter the prostatic part of the urethra. • In females, the ducts then degenerate. In males, the ducts form the origin of the ejaculatory ducts.                                                                                                                     

37. The bladder is initially continuous with the allantois. • Over time, the allantois degenerates to form a cord-like structure, the urachus. • The urachus goes from the umbilicus to the apex of the bladder and forms the median umbilical ligament which can be seen in adults.

38. Clinical problems Urachal anomalies

40. Extrophy of bladder膀胱外翻

41. Normal development of Reproductive System Bipotential Phase Early Development (pre-differentiation) Partitioning of the Cloaca Male Development Development of the Testes Development of External Genitalia Female Development Development of the Ovaries Development of the Vagina Development of External GenitaliaSummary of Derivatives of Embryonic Structures

42. The chromosomal & genetic sex of an embryo is determined at fertilization by the kind of sperm that fertilizes the ovum. • Male & female characteristics begin to develop at the 7th week. • The early genital system in the two sexes are similar  the initial period of genital development is called indifferent stage of sexual development.

43. Early Genital System Development • Early in the 4th week, the primordial germ cells may be seen in the endoderm around the allantois. • These germ cells migrate under the coelomic epithelium, around the gut to the dorsal mesentery.

44. Regulation of germ cell migration

45. 有無不孕症 可能娘胎就決定 2015-06-05 02:48:35 聯合報 記者陳皓嬿、黃筱雅、陳雨鑫／綜合報導

47. Indifferent Gonads • It is the Initial stage in 5th week  thickened area of mesothelium develops on the medial side of the mesonephros  proliferation  form a bulge on the medial side (Gonadal (genital) ridge). • Primary sex cord初級性索( fingerlike epithelial cords)  grow into the underlying mesenchyme. • The indifferent gonad consists of an external cortex and internal medulla • In femalethe cortex of indifferent gonads form the ovary & the medulla regress. • In male the medulla  form the testis & cortex regress except for vestigial remnants. (SRY)

48. Development of the Gonads(Testes & Ovary) • The gonads (testes & ovary) are derived from 3 sources: • The mesodermal epithelium lining the posterior abdominal wall. • The underlying mesenchyme. • The primordial germ cells.

49. Nephorgenic cord: • Mesonephric duct • epidydimis; ductus deferen • Paramesonephric duct • uterine tube; uterus

50. Partitioning of Cloaca Internal structure • The caudal end of the hindgut is lined with endoderm and is known as the cloaca泄殖腔. • At the end of the cloaca, the there is a cloacal membrane泄殖膜 which separates the endoderm from the surface ectoderm.