Formation of the Body Cavities Flashcards
What are the 3 phases of organ development?
growth
morphogenesis - build size and shape due to gene expression
differentiation - cells turn on diff things to perform very specific functions
What nerve innervates the diaphragm?
What are its spinal nerve roots?
phrenic N
C3-C5
What are the pericardial coelom?
originally 2 coelom in lateral plate mesoderm –> merge to form one coelom around developing heart
What is somatopleura?
somatic mesoderm and ectoderm
What does the cephalad longitudinal folding result in?
brain overgrowth –> folds anterior to oropharyngeal membrane and heart –> get septum transversum that is inferior to to developing heart
What is splanchnopleura?
splanchnic mesoderm and endoderm (gut)
What structure do parietal membrane arise from?
somatic lateral plate mesoderm
What structure do visceral membrane structures arise from?
splanchnic mesoderm
What are the endocardial primordia?
2 heart tubes that will merge to form 1
What does the pleuroperitoneal membrane do?
separates the pleural and peritoneal cavities
Where do the lungs develop?
In the area between the pleuropericardial membrane and the pleuroperitoneal membrane
When are the major organs formed during development?
weeks 3-8
At what time do you have a common intraembryonic U-shaped coelom?
What is it formed from?
day 21
formed from coelomic spaces
What type of mesoderm does the pleuroperitoneal membrane arise from?
somatic mesoderm
What is another name for the septum transversum?
central tendon
How is the pericardial cavity separated from pleural canals?
by pleuropericardial folds
What does the diaphragm form from?
pleuroperitoneal membrane grows ventrally toward the septum transversum and they fuse –> tissue from body wall pulled into diaphragm
What folding results in the formation of the intraembryonic coelom?
horizontal folding
What are the major sequences of caudal longitudinal folding?
spinal overgrowth –> folds along w/ hindgut endoderm and allantois–> end up with extraembryonic coelom
What is ectopia cordis?
malfunction in horizontal folding that results in the heart forming outside of the body and a split sternum
What happens in horizontal folding?
somatic lateral plate mesoderm folds down around umbilical vessel and splanchnic mesoderm –> doesn’t completely close –> now you have intraembryonic coelom and the midgut formed by umbilical vesicle shrunken up
What is the order and timing of longitudinal folding
cephalad fold first in early 4th week
caudal fold next in late 4th week
In what embryonic structure does the phrenic nerve start to innervate the diaphragm?
in the pleuropericardial folds
Where do the bronchial buds grow?
into the pericardioperitoneal canals
Along what planes does the embryo fold?
When does this occur?
median and horizontal planes week 4 (simultaneously fold)
