embryology Flashcards
intraembryonic body cavity
forms w/in lateral plate mesoderm
divides lateral plate mesoderm into parietal (somatic) and visceral (splanchnic) mesoderm
patietal -> parietal serousmembranes
visceral-> visceral serous membranes and mm/CT of organs
body folding
fusion of bady wall ventrally
incorportates intraembryonic cavity fully into embryo
retains connection to extraembryonic cavity in midgut until wk 12
cantrells pentology
cleft sternum ectopic cordis gastroschisis or omphalocele diaphragmatic hernia congenital heart defects
septum transversum
plate of mesoderm which separates thoracic and peritoneal cavities
will from bulk of diaphragm
does not completely separate throacic and abdominal cavities; leaves openings on either side of foregut called pericardioperitoneal canals
pluropericardial membrane
separate pleural and pericardial cavities
pleuroperitoneal membranes
separate pleural and peritoneal cavities
fromation of diaphragm
from septum transversum (central tendon and m) pleuroperitoneal membranes (central tendon)
positional changes of diaphragm
mesoderm of diaphragm forms from cervical somites 3-5
differential growth of body leads to decent
by wk 8 diaphragm is at LV1
diaphragm innervation
motor- phrenic n
sensory- central tendon phrenic, m- ICs
bochdack hernia
posterolateral defect
incomplete formation of pleuroperitoneal membranes, usually on left
small intestine and/or other viscera herniate thru defect into pleural cavity
lungs and heart compressed -> pukmonary hypoplasia
morgagni hernia
parasternal hernia
anterior defect in mm of diaphragm
small, sometimes not dectected until child several yrs old
evagination of diaphrgam
weakness (usually unilateral) of diaphragm due to failure of myotome migration
allows abdominal viscera to balloon into thoracic cavity
germ layers
endoderm: epi and glands
mesoderm: CT and smooth m
ectoderm: epi at ends of tube (mouth- stomodeum, lower 1/3 of anal canal- proctodeum)
ends of tube
rostral and caudel ends are originally closed by oropharyngeal and cloacal membranes, rupture during 4th and 7th wk
foregut
pharynx (includes pharyngeal arches0 esophagus stomach parts 1 and 2 duodenum liver gallbaldder pancreas spleen supplied by celiac a
midgut
parts 3 and 4 of duodenum, small intestines ascending colon cecum appendix proximal 2/3s of transverse colon supplied by SMA until wk 10 attached to yolk sac
Hindgut
distal 1/3 of tranverse colon descending colon sigmoid colon rectum proximal anal canal supplied by IMA
esophagus
partly obliterated during wk5, recanalizes by wk 8