Digestive System Embryology Flashcards
(98 cards)
In what week of development does gastrulation begin?
The third week of development
What marks the beginning of gastrulation?
The formation of the primitive streak on the surface of the epiblast
How many of the germ layers contribute to the formation of the digestive system?
All three germ layers
In the GI tract what does the ectoderm form?
Neural crest cells from the neuroectoderm become neurons of the enteric nervous system
In the GI tract what does the mesoderm form?
Connective tissues, muscular components, and peritoneal components
In the GI tract what does the endoderm form?
Epithelium of GI tract and parenchyma of glands
When does the gut tube initially form?
The 4th week of development
What are parenchyma?
the specific cells of a gland or organ held together by connective tissue called the stroma
The stroma of the glands of the GI tract is derived from what?
The visceral mesoderm
Describe neurulation?
The trilaminar embryonic disc forms the neural plate that rolls up into a tube to from the brain and spinal cord
The mesoderm layer of which holds the neural tube and gut tube together splits into two layers during the 3rd and 4th week and are called what?
Visceral (splanchnic) and parietal (somatic) layers
What does the visceral (splanchnic) layer of the mesoderm do in the 3rd and 4th week of development?
Rolls ventrally, and is intimately connected to the gut tube
What does the parietal (somatic) layer of the mesoderm do in the 3rd and 4th week of development?
Together with the overlying ectoderm, forms the lateral body wall folds, which move ventrally and meed in the midline to close the ventral body wall
What does the vitelline duct and yolk sac eventually get incorporated into?
The umbilical cord
When does the yolk sac typically degenerate?
Around 2 to 3 months of development
By the 4th week of development closure of the ventral body wall is complete except where?
At the connecting stalk
By the 4th week of development closure of the gut tube is complete except where?
At the vitelline duct (yolk sac)
What are the three regions of the gut tube?
Foregut, midgut, and hindgut
Define the each end of the foregut in the 4th week of development.
Oropharyngeal membrane to the liver outgrowth
When does the oropharyngeal membrane rupture?
The 4th week
What is connected when the oropharyngeal membrane ruptures?
The oral cavity and the primitive gut
Define each end of the midgut in the 4th week of development.
Begins caudal to liver and extends to proximal 2/3 of transverse colon
Define each end of the hindgut in the 4th week of development.
From distal 1/3 of transverse colon to cloacal membrane
When does the cloacal membrane break down?
The 7th week of development