Embryology Flashcards
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
for how long does reproductive system organogenesis extend
beyond 8 weeks - even extends beyond post natal period
how are the urinary and report systems linked embryologically linked
urinary system for the template for the reproductive system
urinary development recap - three sets of kidneys
Pronephros – cervical region – vestigial
Mesonephros – thoracolumbar region – briefly functional
Metanephros – pelvic region – functional
urinary development recap -
what does the cloaca divide to form
rectum (GI tract) and anteriorly the urogenital sinus
urinary development recap - what drains into the urogenital sinus
the mesonephric duct
urinary development recap - what does the urogenital sinus later go on to form
the urinary bladder, its caudal end forms the urethra
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
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
what is the genital ridge + germ cells known as
the indifferent gonad (hasn’t differentiated yet into male/female)
what happens if the germ cells don’t migrate
no gonads form
how is the paramesonephric duct formed
epithelium of the mesonephros invaginates to form a tube - develops lateral to developing gonads and mesonephric duct
what does the indifferent gonad form eventually
ovary
testis
what does the mesonephrc duct (wolfing duct) form eventually
epididymis, vas deferens, seminal vesicle
what does the paramesnephric duct (mullein duct) form eventually
fallopian tube, uterus, cervix, vagina
