Formation of Body Cavities Flashcards
gastrulation
Establish 3 embryonic germ layers: ectoderm, mesoderm, endoderm
trilaminar disc has 3 layers everywhere EXCEPT:
1) bucopharyngeal membrane - will form oral cavity
2) cloacal membrane - will form anus
ectoderm fuses with endoderm so mesoderm cannot penetrate
paraxial mesoderm forms
somitomeres, somites
intermediate mesoderm forms
urogenital system
layers of lateral plate mesoderm
somatic layer (parietal) splanchnic layer (visceral)
When taco folding (lateral folding) happens, they become parietal and visceral layers of body cavities.
intraembryonic coelom of lateral plate mesoderm
future pericardial/pleural/peritoneal cavities
transformation of flat trilaminar disc to 3D embryo
Cephalic fold.
Caudal fold.
Two lateral folds.
lateral folding of embryo
Converts yolk sac into a gut tube (future foregut/midgut/hindgut)
growth of forebrain
Behind buccopharyngeal membrane.
Results in head fold.
Puts mouth in correct location.
growth of spinal cord
Results in tail fold.
Puts anus in correct location.
intraembryonic cavity can be divided into
pericardial cavity, pericardioperitoneal canals, peritoneal cavity
divided by septum transversum
septum transversum location, innervation
Starts at C1.
Ends at T7 in front, T12 in back.
Myoblast migration muscularizes ST (diaphragm) – from C3-5 (phrenic nerve)
forms CENTRAL TENDON and ANTERIOR DIAPHRAGM
pleuroperitoneal membranes
finish closing the foregut, where septum transversum stops.
defect causes congenital diaphragmatic hernias
POSTERIOR part of diaphragm
R/L crura formed from
mesenchyme surrounding esophagus
formation of costodiaphragmatic angle/recess
pleura burrows down and grows downward
