Embryology Flashcards
What is the first phase of embryo development?
Growth/proliferation
What is the second phase of embryo development?
Morphogenesis
What is the third phase of embryo development?
Differentiation
The cranial part of the primitive gut tube forms
The oesophagus
Laryngotracheal diverticulum
Develops from the ventral wall of the foregut, forms lung bud
Tracheoesophageal septum
Divides the foregut tube into trachea and oesophagus
What happens when the tracheoesophageal septum deviates incorrectly?
Incomplete separation of laryngotracheal tube resulting in oesophageal atresia and tracheoesophageal fistula
How many times does the stomach rotate in the developing embryo?
Twice
90 degree rotation around its own longitudinal axis
Anterio-posterior axis rotation
In what week does the foregut dilate to form the stomach?
4th week
What creates the lesser sac?
The longitudinal rotation of the stomach pulls the dorsal mesentery to the left
The caudal part of the foregut and the cranial part of the midgut form
The duodenum
What causes the duodenum to be C shaped?
The rotation of the stomach along the anterio-posterior axis
The outgrowth of endoderm in the distal foregut forms which bud?
Liver bud (hepatic diverticulum)
The connection between the liver bud and the duodenum narrows to form
The bile duct
The gallbladder and the cystic duct are formed from
The ventral outgrowth from the bile duct
What forms the spleen in week 5?
Differentiation of a mesenchymal condensation in the dorsal mesogstrium from end of week 4
Spleen acts as a haematopoietic organ until
Week 14
What happens to the spleen during weeks 15-17?
Acquires its lobular shape and is colonised by T-lymphocytes
After week 23 the spleen starts its lymphoid function due to
The arrival of B-cell precursors
How many buds form the pancreas?
2, grow from endodermal lining of the duodenum
The ventral bud froms
The uncinate process and inferior part of the head of the pancreas
Main pancreatic duct formed from
Ventral duct plus distal part of the dorsal duct
In what week does rotation of the midgut begin?
Week 6
Why does the gut tube herniate?
Liver and Kidneys develop quicker and take up too much space
In what week does the gut tube move back into the body cavity?
Week 10. Liver growth slows, abdominal cavity space increases.
What is Ompalocele?
Herniation of the abdominal viscera through an enlarged umbilical ring
Remnants of a vitelline duct can form?
Meckel’s diverticulum
