Digestive System Development Flashcards
oropharyngeal membrane is made up of ______
ectoderm & endoderm
gastrulation
establishes the 3 germ layers within the embryo - ectoderm, mesoderm, endoderm
All three germ layers contribute to the formation of the digestive system
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ectoderm’s role
neural crest cells from neuroectoderm become neurons of the enteric system
mesoderm’s role
connective tissue, muscular components, and peritoneal components
endoderm
epithelium of GI tract and parenchyma of glands
cranial/caudal folding
sagittal - growth of the head and tail regions that cause the embryo to curve into fetal position - opens the gut tube into the yolk sac narrows - forms a small connection (vitelline) - incorporated into the umbilical cord
lateral folding
grows ventrally - consists of the parietal somatic layer and overlying ectoderm - folds meet in the midline & fuse to close ventral body
gut tube is divided into 3 regions
foregut, midgut, hindgut
foregut
extends from oropharyngeal membrane to liver outgrowth -
oropharyngeal membrane
separates the stomodeum from the pharynx
midgut
begins caudal to the liver and extends to proximal 2/3 of transverse colon
hindgut
from the distal 1/3 of the transverse colon to the cloacal membrane (ectoderm & endoderm form this membrane)
mesentery
double layer of peritoneum that encloses an organ and connects it to the body wall
intraperitoneal
organs which are completely enclosed in mesentery and connected to wall via mesentery
retroperiotneal
organ that lies against the posterior body wall and is covered with periotneum on anterior surface only
dorsal mesentery
formed via visceral mesoderm layers and meeting and fusing in midline - suspends the caudal part of the foregut, the midgut, and some of the hindgut
divisions of the dorsal mesentery
dorsal mesogastrium, mesoduodenum, dorsal mesocolon, mesentery proper
dorsal mesogastrium
greater omentum - dorsal mesentery in region of the stomach