19. Embryology 3 Flashcards Preview

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Flashcards in 19. Embryology 3 Deck (20):

When does development of the lung begin?

Week 3


How does the liver begin developing?

The hepatic diverticulum (liver bud) starts as an out-pocket of the duodenum.
It develops very quickly and penetrates the septum transversum (future diaphragm).
Here it develops further.


How is the bile duct formed?

The connection between the hepatic diverticulum and duodenum narrows to form bile duct.


What germ layer is the liver formed from?

Endoderm = Hepatocytes
Mesoderm = Heamotopoietic, Kupffer cells, connective tissue


The liver develop in the dorsal mesentery.
True or False?

Ventral Mesentery


The liver causes a mesentery to divide into 2 parts.
Identify these.

Ventral mesentery:
1. Falciform ligament
2. Lesser omentum


What is the 'bare area' of the liver and what are its boundaries?

Area of liver with no peritoneum (basically stuck to diaphragm).
1. Coronary ligaments - outline area
2. L+R Triangular ligaments - Edges where coronary ligaments join


The liver is larger shrinks at birth.
True or False?

Switches function from making red blood cells to filtering blood


The cystic duct is formed from an outgrowth of gut tube.
True or False?

Outgrowth from bile duct. Gallbladder also develops from the bile duct.


Why is a baby's first poop dark green?

High bile concentration.
A load of bile that had been chilling in the gut tube during development is excreted.


What is the cause of neonatal jaundice?

If the liver cannot yet conjugate bilirubin, it cannot be excreted.
Therefore, it collects in the body and causes yellow skin and sclera (whites of eyes).


How and why is neonatal jaundice treated?

Kernicterus = Excess unconjugated bilirubin crosses the blood-brain barrier and cause brain damage.
Phototherapy breaks down the bilirubin so that it can be excreted.


What is biliary atresia and how does it occur?

Narrowing of the biliary system tubes which prevents bile from passing into intestine.
This can occur if recanalisation of the hepatic or bile duct fails.
Similar symptoms as jaundice, but cannot be treated by phototherapy.


How does a duplicated gall bladder arise?

An extra out-pocket of endoderm instead of just one.


How does the pancreas begin developing?

2 endodermal buds fuse - ventral & dorsal buds around duodenum.
When the stomach rotates (90 clockwise) the ventral bud is rotates lie behind the dorsal bud & fuse.
Ventral bud forms 'uncinated process'.
Dorsal bud forms the rest of pancreas.


The main pancreatic duct & the accessory pancreatic duct both enter the intestine at the Ampulla of Vater.
True or False?

Accessory pancreatic duct enters into intestine separately.


What is an annular pancreas & how does it occur?

Obstruction of duodenum by pancreas.
If the ventral bud is bilobed (two buds), each bud can go to either side of the duodenum during rotation and compress the tube.


What is ectopic pancreatic tissue?

Pancreatic cells that develop in places they shouldn't be.


How does the spleen begin developing?

Derived from mesoderm(unlike rest of abdominal organs).
Week 5 forms in dorsal mesentery.
Rotation of stomach brings it onto left hand side.


Where is the lienorenal ligament found?

Lienorenal ligament = dorsal mesentery between spleen & kidney