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Flashcards in Embryology Deck (17):
1

give a brief time line of embryological events

Weeks 1 & 2

Week 3 – gastrulation, neurulation, somite formation

Weeks 4 – 8 organogenetic period

Week 9 onwards – maturation of organ systems

2

for how long does reproductive system organogenesis extend

beyond 8 weeks - even extends beyond post natal period

3

how are the urinary and report systems linked embryologically linked

urinary system for the template for the reproductive system

4

urinary development recap - three sets of kidneys

Pronephros – cervical region – vestigial

Mesonephros – thoracolumbar region – briefly functional

Metanephros – pelvic region – functional

5

urinary development recap -
what does the cloaca divide to form

rectum (GI tract) and anteriorly the urogenital sinus

6

urinary development recap - what drains into the urogenital sinus

the mesonephric duct

7

urinary development recap - what does the urogenital sinus later go on to form

the urinary bladder, its caudal end forms the urethra

8

what happens in weeks 5-6 of repro organ development

genital (gonadal) ridge formation
- mesonephros froms a long ovoid structure with the thoracic and upper lumbar vertebrae
- medial part of mesonephric ridge becomes thickened to for a genital/gonadal ridge

9

what happens once the genital ridge has formed

germ cells migrate from the yolk scan, via dorsal mesentery, and embed into the primitive sex cords (formed from the mesenchyme of the genital ridges

10

what is the genital ridge + germ cells known as

the indifferent gonad (hasn't differentiated yet into male/female)

11

what happens if the germ cells don't migrate

no gonads form

12

how is the paramesonephric duct formed

epithelium of the mesonephros invaginates to form a tube - develops lateral to developing gonads and mesonephric duct

13

what does the indifferent gonad form eventually

ovary
testis

14

what does the mesonephrc duct (wolfing duct) form eventually

epididymis, vas deferens, seminal vesicle

15

what does the paramesnephric duct (mullein duct) form eventually

fallopian tube, uterus, cervix, vagina

16

male summary:

gonad forms testis

mesonephric duct develops into epididymis, max deferent, seminal vesicle

paramesonephric duct degenerates

urogenital sinus forms bladder, urethra, prostate

17

female summary

gonad forms ovaries

mesonephric duct degenerates

paramesonephric duct forms fallopian tube, uterus, cervix, upper part of vagina

urogenital sinus forms bladder and lower part of the vagina