BIOM3002 Lecture Notes - Lecture 4: Superior Mesenteric Artery, Urogenital Sinus, Vitelline Duct
26 May 2018
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EMBRYOLOGY LECTURE FOUR
Q. When (weeks) does 'simple tube' -> 'coiled tube'?
A. 7-11 weeks
3 x types Meckel's diverticulum:
1. Finger-like projection ~3cm
2. Fibrous cord – can wrap around ileum and cause death of
ileum [blood supply problems]
3. Fistula – connection ileum to outside and seepage of
material outside
Allantois [evolutionary remnant from birds – allows exchange
of gases and exchange of nutrients] NOT needed in animals
Top loop = foregut
Bottom loop = midgut
Between = superior mesenteric artery
Vitelline duct -> yolk sac [source of nutrition]
LHS = cardiac primordia
RHS = allantoic diverticulum in body stalk
Urinary bladder -> umbilicus [fistula = weeping urine]
Should degenerate in placental animal
Urogenital system [development of cloaca]
• Originally separated from external world by membrane
[all connection = umbilicus -> yolk sac]
• Endodermal pouch; ectodermal cloacal membrane
Weeks 4-6, mesodermal folds create septum [urorectal septum]
Urinary sinus -> urinary system [bladder, urethra]
Perineum [fibrous, remains]
Anorectal canal
In females, vagina forms between anorectal canal and urethra
How urogenital and reproductive systems merge together and
come out of tissue [4th week]:
Intermediate mesoderm -> differentiates to form PRO-NEPHROI
[remnant in humans, quickly degenerates, non-functional] at
rostral end
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Embryology lecture four: when (weeks) does "simple tube" -> "coiled tube", 7-11 weeks. 3 x types meckel"s diverticulum: finger-like projection ~3cm, fibrous cord can wrap around ileum and cause death of, fistula connection ileum to outside and seepage of ileum [blood supply problems] material outside. Allantois [evolutionary remnant from birds allows exchange of gases and exchange of nutrients] not needed in animals. Vitelline duct -> yolk sac [source of nutrition] Urinary bladder -> umbilicus [fistula = weeping urine] Urogenital system [development of cloaca: originally separated from external world by membrane. [all connection = umbilicus -> yolk sac: endodermal pouch; ectodermal cloacal membrane. Weeks 4-6, mesodermal folds create septum [urorectal septum] In females, vagina forms between anorectal canal and urethra. How urogenital and reproductive systems merge together and come out of tissue [4th week]: [remnant in humans, quickly degenerates, non-functional] at rostral end.
