Embryology Flashcards Preview

Repro > Embryology > Flashcards

Flashcards in Embryology Deck (59)
Loading flashcards...
1
Q

Intermediate mesoderm will give rise to:

A

GU

2
Q

Intermediate mesoderm will later be called:

A

urogenital ridge (2, on either side of midline)

*name change once arranged cranial-caudally

3
Q

How does GU develop in earlier stages?

A

cranial-caudal, along full length of UG ridge

4
Q

How do gonadal/genital parts develop in earlier stages?

A

along medial + central portion of UG ridge

5
Q

What are the 3 stages of kidney development (start in 4th week)?

A
  1. pronephros (non-functional, disappears early)
  2. mesonephros (functional from week 5 to ~week 9)
  3. metanephros (functional begining in 2nd trimester)
6
Q

mesonephros consist of:

A

nephron

mesonephric duct

7
Q

During kidney development, as _____ portion is developing, ____ portion is regressing.

A

caudal

crainial

8
Q

Separate draining systems that exist during kidney development?

A

mesonephrus

9
Q

Mesonephric duct is aka

A

Wollfian duct

10
Q

What portion of the mesonephros does NOT regress?

A

mesonephric duct

11
Q

What are the 2 parts of metanephros?

A

ureteric bud (grows out of mesonephric duct)

metanephric blastema/mass

12
Q

Metanephric duct drains into

A

cloaca

13
Q

What would causes congenital absence of kidney on 1 side?

A

ureteric bud or metanephric blastema/mass fail to develop

14
Q

Ureteric bud develops to form:

A

calyces, pelvis, ureter

all the parts that drain urine!

15
Q

Doubling of ureteric bud results in:

A

doubling of ureters

16
Q

What is an ectopic ureter?

A

ureter develops abnormally and misdirects urine to area other than bladder, causes incontinence
(Female commonly = vagina, urethra, vestibule; Male commonly = bladder neck, prostatic urethra)

17
Q

What structure forms the nephron?

A
metanephric blastema (mass)
**forms cortex/medullary
18
Q

Metanephric blastema develops from:

A

metanephric caps on ureteric buds

19
Q

3 conditions related to abn renal development?

A

unilateral renal agenesis (most commonly M + L side)

unilateral hypoplastic kidney

supernumerary kidney

20
Q

What condition results from bil renal agenesis, and why is it so bad?

A

Potter’s sequence
Most common cause of oligohydroaminos (fetus takes in amniotic fluid, but can’t send it back out)

**also causes facial abn, clubbing of hand, hypoplastic lungs

21
Q

What causes the movement of kidneys during development?

A

“body grows out from under them”

some upward pull PLUS they do not descend along with pelvis + trunk, which grow downward and disproportionately (relative to upper trunk)

22
Q

What causes a “pelvic kidney?”

Why would this be a problem?

A

kidney is “caught” and descends with the pelvis abnormally

if it were to rotate, ureter may become obstructed

23
Q

What is a horseshoe kidney?

A

renal poles fuse, causing grossly abn but functionally normal kidney; get stuck at inferior mesenteric artery

24
Q

What divides UG sinus from anorectal canal?

A

urorectal septum

25
Q

What was the original space which is divided into the UG sinus + anorectal canal?

A

cloaca (hindgut)

26
Q

The urogenital sinus forms:

A

bladder, urethra, prostate, lower vagina

27
Q

What layer is distal urethra originally derived from?

A

ectoderm

28
Q

How does the positioning of the ureter and vas deferens develop?

A
  • -mesonephric duct and ureteric bud eventually separate
  • -the ureteric duct connects directly/independently to the posterior bladder
  • -mesonephric duct descends downward, but remains hooked over the ureter
29
Q

What path do primordial germ cells talk to reach gonad?

A
  1. originate in yolk sac
  2. migrate through connecting stalk
  3. pass through dorsal body wall
  4. populate gonads (bilaterally at urogenital ridge)
30
Q

What does the yolk sac originate from?

A

extra-embryonic tissue

31
Q

When do germ cells migrate?

A

4th-6th week

32
Q

What occurs once the germ cells reach the gonads (male vs female)?

A

males: remain dormant until puberty, then meiosis
female: immediate meiosis I

33
Q

What occurs to the gonad following primordial germ cell migration?

A

remains in “indifferent” stage, does not have M or F characteristics

34
Q

What are the 3 components of an indifferent gonad?

A
  1. primordial germ cells present
  2. primary sex cords (grow from surface epith)
  3. 2 duct system (mesonephric + paramesonephric)
35
Q

What effect does the absence of testerone have on sex cords?

A

primordial follicles = regress, break into segments

36
Q

What effect does testosterone have on sex cords?

A

Become semeniferous tubules = length, coil, form lumen

37
Q

Each follicle in an ovary contains:

A

one primordial germ cell

38
Q

Wolffian ducts form…

Mullerian ducts form…

A

M genital tract
F genital tract

**only keep 1 duct

39
Q

4 classic proteins/hormones in 7,8,9th week, which drive male development:

A
  1. Testes determining factor
  2. T (Leydig cells)
  3. MIF (Sertoli cells)
  4. DHT (requires 5aR)
40
Q

Early production of ___ drives male development.

A

T

41
Q

Where does testes determining factor develop?

A

short arm of Y chromosome

SRY gene codes for TDF

42
Q

Why is it easier to develop an ovary?

A

develop by the ABSENCE of Y chromosome, which = absence of TDF

43
Q

What is the function of MIH?

A

secreted by testes to drive suppression fo paramesonephric ducts

44
Q

What drives female duct development?

A

E

45
Q

Paramesonephric ducts ultimately become:

A

uterine tubes
uterus
upper part of vagina (two portions fuse)
(all from mesoderm)

46
Q

What layer does the lower part of the vagina develop from?

A

ectoderm

47
Q

Remnant of mesonephric duct which may become infected?

A

Gertner’s cyst

48
Q

Congenital abn are usually resultant from:

A

abn fusion of paramesonephric ducts

49
Q

How does male external genitalia develop from the indifferent stage?

A
  1. genital swellings fuse into midline = scrotum
  2. genital tubercle forms glans
  3. UG fold fuses along ventral shaft
50
Q

How does female external genitalia develop from the indifferent stage?

A
  1. genital tubercle forms clitoris
  2. genital swelling becomes labia majora
  3. UG folds form labia minora
51
Q

Hypospadias is caused by…

Epispadias is caused by…

A

failure of UG folds to fuse:
ventrally = hypo
dorsally = epi (can extend along abd)

52
Q

How/when do testis/ovary migrate?

A

in last trimester, ovary/testes departs from UG ridge in lateral body wall

53
Q

What is processus vaginalis?

A

piece of peritoneum captured during descent, remains in scrotum with testis (later called tunica vaginalis, reduces ball friction)

54
Q

What is the gubernaculum?

A

CT that = pathway of testis into scrotum

55
Q

What does a patent processus vaginalis cause?

A

congenital indirect inguinal hernia

56
Q

What does excess fluid of tunica vaginalis cause?

A

hydrocele

57
Q

Ovarian tissue with masculinization of female ext genitalia =

A

female intersexuality due to congenital adrenal hyperplasia

58
Q

Testicular tissue with stunted male ext genitalia =

A

female intersexuality caused by inadequate T/MIH by testes

59
Q

XY but develops testes located within labia majora, has female ext genitalia =

A

androgen R mutation