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Flashcards in Development Deck (62):
1

Urogential Ridge

intermediate mesoderm --> urogenital ridge
nephrogenic ridge -> urinary system
gonadal/genital ridge -> gential system

2

Pronephric phase

pronephros arise in cervical region and give rise to pronephric duct --> grows caudally and opens into cloaca
- eventually degenerates

3

Mesonephric phase

pronephric duct becomes mesonephric duct

4

Metanephric phase

definitive kidney

5

Mesonephros

gives rise to the mesonephric tubules that become efferent ductules of male testis

6

Ureteric Buds

mesonephric duct in male gives rise to ductus deferens in male
- also gives rise to ureteric buds in both male/female
Ureteric buds -> grow into intermediate mesoderm and initiate formation of definitive kidney
- gives rise to ureter, renal pelvis, calyces, collecting ducts

7

Nephrons

Bowman's capsule, proximal tubule, loop of Henle, distal tubule
- arise from intermediate mesoderm through induction by arched collecting tubules

8

Glomerulus

formed by endothelial cells growing into renal capsule

9

Uriniferous tubules

consist of nephron and collecting ducts

10

Metanephric kidneys

definitive kidneys
- located deep in pelvis but ascend into abdomen later in development

11

Renal Agenesis

failure of ureteric bud and metanephric mesoderm to interact
- more common on L and in males
- if bilateral --> death
*suspect in single umbilical artery patients*

12

Duplicated/branched ureter

bifurcation of ureteric bud

13

Ectopic ureter

ureter enters urogential sinus derivative at some site other than dorsolateral wall of urinary bladder

14

Supernumerary kidney

due to divison of ureteric buds and interaction with areas of metanephric mesoderm

15

Pelvic kidneys

failure of kidney to migrate from pelvis

16

Crossed kidney

kidney migrates to opposite side and kidneys fuse

17

Horseshoe kidney

2 kidneys fuse at inferior poles and migration is blocked by inferior mesenteric artery

18

Multiple renal arteries

due to segmental blood supply during development

19

Urorectal septum

mesoderm origin --> divides cloaca into rectum and urogenital sinus

20

Urogential sinus

continuous with allantois --> extends to body stalk
- vesicle part -> forms urinary bladder (continuous with allantois which becomes urachus)
- pelvic part -> becomes bladder neck and prostatic urethra in male, full urethra in female
- phallic/spongy part -> grows toward genital tubercle

21

Perineal Body

forms where urorectal septum comes in close contact with cloacal membrane

22

Mesonephric ducts and ureteric bud

incorporated into posterior wall of developing urinary bladder
- results in trigone of bladder formed by mesonephric duct

23

Epithelium of entire bladder

ENDODERM of urogential sinus

24

Urethra

Proximal male -> urogential sinus
Distal male -> ectoderm
Female -> urogenital sinus

25

CT and smooth muscle of bladder

splanchnic mesoderm

26

Urachal sinus and fistula

Sinus --> secretion of fluid (not urine)
Fistula --> need to see if it is urine or fecal material

27

Exstrophy of bladder

bladder that opens onto anterior abdominal wall
- lack of anterior wall mesoderm to close during 4th week

28

Megacyst

ONLY in MALE
- posterior urethral valves don't undergo apoptosis during development and block outflow of urine
- leads to renal failure and pulmonary hypoplasia

29

Adrenal Medulla

neural crest cells --> chromaffin cells

30

Adrenocortical primordia

cranial part of urogenital ridge
- cortex develops from mesoderm located on posterior ad wall
Fetal cortex --> large size
Permanent cortex -> develops later and replaces fetal cortex

31

Congenital Adrenal Hyperplasia

many clinical forms, due to enzyme deficiencies
- 21-beta hydroxylase gene is most common

32

Genetic sex determination

at time of fertilization, but phenotypic sex is determined at 7th week of development

33

Phenotypic maleness

presence of Y chromosome --> SRY protein --> testicular determining factor --> development of testes

34

Phenotypic female

2 X chromosomes -> absence of Y chromosome

35

Klinefelter syndrome

47 XXY -> nondysjunction of XX homologues
- infertility, gynecomastia, and impaired sex maturation

36

Turner syndrome

46 XO -> failure of gonads to develop and infantile genitalia -> lack of paternal sex chromosome
- short stature, high palate, webbed neck, broad-shield chest, widespaced-inverted nipples, absence of sexual maturation

37

Ovotesticular disorder

hermaphrodites (disorder of sexual development)
- possess both testicular and ovarian tissue

38

Migration of gametes from umbilical vesicle

into genital ridge during sex development
- primordial germ cells enter genital ridge during 5th week
- caudal end = gonads
- developing gonads consist of mesothelium, mesenchyme, and primordial germ cells

39

Cortical cords

Male - germ cells migrate to cortical cords and form seminiferous tubules --> precursors of sertoli cells
Female - cortical cords break apart and form follicular cells

40

Efferent ductules

form from mesonephric ducts and become epididymis

41

Interstitial cells of Leydig

develop from mesenchyme and synthesize androgens

42

Sertoli Cells

don't mature during fetal period but under influence of hCG -> produce anti-Mullerian hormone --> suppress paramesonephric ducts

43

Oogonia

formed from primordial germ cells --> meiosis stimulating factor --> enter meiosis I --> primary oocyte

44

Differentiation of Male Sexual Duct System

- anti-Mullerian hormone from Sertoli Cells -> paramesonephric ducts degenerate -> leaving prostatic utricle
- testosterone causes mesonephric ducts to become epididymis, ductus deferens, ejac duct

45

Differentiation of Female Sexual Duct System

If ovaries present or gonads absent, ducts differentiate into female phenotype
- absence of anti-Mullerian hormone allows paramesonephric ducts to develop (uterine tubes and uterus) --> travel caudally and fuse to form uterovaginal primordium --> makes sinus tubercle

46

Upper 1/3 of vagina

develops from paramesonephric ducts

47

Lower 2/3 of vagina

develops from vaginal plate derived from urogential sinus

48

Greater vestibular glands

bulbourethral glands

49

Paramesonephric duct agenesis

complete/partial absence of uterine tubes, uterus, cervix, and vagina --> shallow vagina
- normal ovarian cycle but no menstruation

50

Double uterus and double vagina

paramesonephric ducts fail to fuse

51

Double uterus and single vagina

only distal end of paramesonephric ducts fuse

52

Bicornuate uterus

defective fusion of paramesonephric ducts

53

Uterine septum

incomplete resorption of tissue of developing uterus

54

Unicornuate uterus

only 1 paramesonephric duct develops

55

Absence of uterus and vagina

failure of uterovaginal primordium to form and induce formation of sinus tubercle

56

Migration of gonads

Male - gubernaculum guides testis down through deep inguinal ring and under influence of androgens
Female - gubernaculum becomes ligament of ovary and round ligament of uterus

57

Cryptorchidism

undescended testes - results in sterility and increased risk of cancer

58

Ectopic testis

due to migration of testis to some other site because of abnormal location of gubernaculum

59

Congential inguinal hernia

indirect hernia
- peritoneal cavity fails to close

60

Hydrocele

accumulation of fluid in remains of process vaginalis

61

Male external development

testosterone --> DHT
- produces masculinization by stimulating phallus to enlarge and elongate - penis
- urogential folds fuse to form spongy urethra
- ectodermal cord grows to form glans
- labioscrotal swellings form the scrotum

62

Female external development

lack of testosterone -> estrogens induce feminization
- phallus becomes clitoris
- urogenital folds become labia minora (space is vagina)
- labioscrotal swellings form labia majora