Gi Development Flashcards
What are the three layers of Gastrulation?
Ectoderm
Mesoderm
Endoderm
In gut formation, which layer wraps around the other two ?
Ectoderm
Which layer is the gut made up of?
Endoderm
What does the cloaca separate?
Bladder and rectal regions
The concentration of what sets up regionalisation?
Retinoic acid
What forms in areas where there is a lack of retinoids acid?
Pharynx
What forms in areas of high retinoic acid?
Colon
What else plays a role in regionalisation?
Mesoderm and endoderm interact
SHH
What is the pharynx formed of?
Top is ectodermal
Lower is endodermal
What joins to form the neck?
Pharyngeal arches and pouches
What does the 1st pair of pharyngeal pouches form?
Auditory cavities
What does the 2nd pair of pharyngeal pouches make?
Tonsils
What does the 3rd pharyngeal pouches form?
Thymus
What does the 4th pair of pharyngeal pouches make?
Parathyroid gland
What is the mesentery?
The stalk that attaches the gut tube to the fetus
What does the mesentery allow passage of into the GI?
Nerves blood vessels
What is the septum transversum?
Mesenchyme in the embryo that forms the gut
What does the ventral mesentery form?
Upper part of GI
What does the liver split the ventral mesentery into?
Lesser omentum and falciform ligament
What happens to the stomach as it grows?
It rotates 90 degrees moving the small intestine and pancreas
What does canalisation do?
Reopens the lumen of the duodenum
What happens if canalisation doesn’t happen?
Will cause a blockage leading to a build up of amniotic fluid
What happens during mid gut development?
Rapid elongation
Looping
Herniated into umbilical cord for growing space
What layer forms the liver pancreas and gall bladder?
Endoderm
What induces liver development?
Proximity to heart
What specifies development of hepatocytes?
Hepatocyte growth factor HGF
What do cholangocytes form?
Bile duct cells
How is the pancreas formed?
Ventral and dorsal buds rotate and join
Which bud forms the uncinate process of the pancreas?
Ventral
What stimulates the development of pancreas?
Notochord
If Ngn3 is present which cell type will form?
Endocrine
Why must baby’s get lipase from milk?
They cannot digest protein as pancreas only becomes functional as an adult
Why do GI cells constantly regenerate?
High throughput and thus attrition
How does gi maturation occur?
Cells move to top of villi and undergo anoikis
What is anoikis?
Cell death due to loss of attachment
