embryology Flashcards
ectoderm forms what?
skin
cns
pns
glands
endoderm forms what?
epithelial lining of git and resp tract
liver
pancreas
mesoderm forms what?
muscles, bones, cartilages, spleen etc
organogenesis occurs when?
week 3-8
how is gut tube formed?
endodermal lining of yolk sac - formed by folding of embryo
how is gut tube still connected ?
conne ted temporarily to yolk sac by vitelline duct
ventral and dorsal meaning?
ventral - anterior
dorsal - posterior
ventral mesentery splits to? and why?
due to liver growing here
falciform ligament(anterior) and lesser omentum
how do organs form from gut tube?
as outpouchings
how intestines from from gut tube?
grow first and grow into umbilicord and retract back into abdomen - physiological herniation
how does oesophagus form?
as a lung bud forms from front wall of forgot and splits by tracheostomy’s-oesophageal septum into trachea and oesophagus
what rotation does the stomach undergo around? and what does it form?
longitudinal axis and anterograde-posterior axis
forming the curves and parts of stomach
duodenum forms from? and how does it rotate?
cadual part-end of foregut
and cranial part -start of midgut
duodenum forms c shape as stomach rotates too and presses against it
how does liver form?
development depends on?
as a liver bud outgrowth from anterior wall of distal foregut
foregut and septum trasnversum
septum transverse forms?
cells, connective tissue and central tendon of diaphragm
spleen develops where?
in dorsal mesentery
how does pancreas develop?
by two separate pancreatic buds - dorsal and ventral - both outgrowths of duodenum
when duodenum rotates and pulls these buds together and fuse
what is the primary intestinal loop?
what the midgut undergoes to form loops of intestine - grows into umbilicus and rotates anti-clockwise around axis of SM artery and retracts back into abdomen
omphalocele?
failure of retraction of herniated intestinal loop
what SHOULD HAPPEN to vitelline duct?
should obliterate !
origins of hindgut development/parts?
endodermal origin - 1/ 3colon to anal canal
ectodermal origin - lower part of anal canal and orifice
cloacal membrane? formed how?
formed by ectoderm and endoderm coming in contact with each other
membrane that covers over development of urinary and reproductive organs
what should happen to cloaca?
perforates and no longer exists in living being
