GIT Embryo Flashcards
The foregut extend from the _____ to ____
Buccopharyngeal membrane to swptum transversum
The midgut extend from the _____ to ____
Vitelline tube and yolk sac
The hindgut extend from the _____ to ____
Allontoic diverticulum extends to cloacal membrane
The foregut is divided into? Namely
3
1st part– pharynx = paired branchial arches
2nd part– thoracic= respiratory bud and oesophagus
3rd part– abdominal= passes the septum transversum and forms abdominal part of oesophagus, stomach, half of the duodenum
____ supplies the yolk sac and forms a plexus around the gut,
And develops into the arterial supply of the abdominal gut?
Vitelline arteries
_____ supplies the arteries of the gut
Dorsal aorta
____ is the main artery from which the foregut, midgut and hindgut are supplied
Vitelline artery
What branches of the vitelline artery supplies
Foregut, midgut and hindgut
Coeliac aixis-forgut(in septum transversum)
Superior mescentric artery (supplies midgut)
Inferior mescentric artery (hindgut)
The splanchnic secondary mesoderm forms
Smooth muscles and CT
The GIT is formed from ______
The incorporation of the dorsal part of the yolk sec into the embryo due to head, tail and lateral fold
The foregut extends from____ to _____
Pharynx to middle 2nd part of the duodenum
The midgut extends from____ to _____
2nd half of the duodenum to junction btw medial 2/3 and lateral 1/3 of the transverse colon
The hindgut extends from____ to _____
Medial 2/3 or lateral 1/3 downwards
What are the derivative of the foregut?
Pharynx, oesophagus, stomach, 1st and half of the 2nd part of the duodenum, liver, gall bladder, spleen, pancreas, respiratory system
What are the derivative of the midgut?
(Half of the 2nd part of the )3rd,4th duodenum, jujenum, ileum, appendix, caecum, ascending colon, right colic flexture, medial 2/3 of the transverse colon
What are the derivative of the hindgut?
Left 1/3 of the transverse colon, left colic flexture, decending colon, segmoid colon, rectum, upper1/2 of anal canal, primitive urogenital derivatives
@_____ week the respiratory diverticulum appears @ ____ wall of the foregut?
4 week
Ventral wall
The oesophagus develops from the ____ part of the respiratory diverticulum
Posterior part
The oesophagus is first short the elongates
What are the conginal defects of the oesophagus?
Tracheo-oesophageal fistula— non separation between the oesophagus and the trachea
Oesophagial atresia– due to failure to recanlize
Oesophagial stenosis— due to incomplete recanalization
What are the stages of oesophagial development?
Elongation- 2nd month
Recanlization- 3rd month columnar Epithelium
Differentiation– 4th month stratified squamous Epithelium
Induction–
Trans differentiation– smooth muscle to skeletal @ 2/3 of the oesophagus
From week ___ to ___ the stomach grows in all directions and become sac like
And the lesser and greater curvature forms @___ week
Achieve its characteristic shape @____ week
4th to 8th
5th
8th
In the stomach,
The foregut forms___, ___&____
Splanchnic mesoderm forms___, ___&___
Neural crest forms ____&____
For– epithelium, gastric pit, gastric gland
Span Meso– CT, smooth muscle, blood vessels
Neural C– automatic nerve plexus, sub mucosal and myenteric
The stomach appears as fusiform dialation of the forgut @____ week
4th
@ stomach development
The left vagus nerve becomes _____
And right vagus N becomes ____
Ant. Gastric N
Pst. Gastric N
In stomach development
The pyloric end moves to the ____ and cardiac end move to ____ due to ____
Right
Left
Development of the Liver
The stomach muscle develops @ ___ week
The gastric gland development @ _____ time
Rennin starts functioning @ ____ time?
8-9 weeks
Gland-3rd month
Rennin- 5th month
Differentiation of the stomach occur between ___ and ___
Chief and parietal cells forms @ ____ to ___ weeks
Glands becomes fully functional @ ____ to ___ time
2nd and 3rd month
10-20 weeks
8-9th month
The stomach develops in ____ and has both ____ and ____ mesentery
Septum transversum
Dorsal amd ventral mesentery
The spleen develops in _____
The liver develops in______
Spleen– dorsal mesentery
Liver– ventral mesentery
The stomach undergoes 90degree rotation @ ___ weeks
5th
The duodenum is derived from?
Terminal end of the foregut and proximal end of the midgut
The duodenum receives blood from?
Forgut(colic artery) and midgut(superior mesentery)
The duodenum becomes C shaped due to ___ growth?
The duodenum rotates_____
Differential growth
90degrees to the right
The duodenum losses it’s mesentery and becomes a ___ organ
Secondary retro- peritoneal
____ gives rise to the liver and pancreatic buds
duodenum @ the distal foregut
Hepatic buds develops @ ____
Ventral border of the foregut (duodenum)
The hepatic bud forms ____ and ____
Which turns into
Par hepatica (liver) and par cystica (gall bladder & cystic duct )
The par hepatica divides I to 2 enters the Septum transversum and forms
Hepatic duct
Liver cells
Epithelial lining of bile canulliculi
Septum transversum forms
Falcuform ligament, lesser omentum, liver capsule
The pancreas develops from the___&___pancreatic bud from the ____ of the DUODENUM
Dorsal and ventral buds
Endoderm of the duodenum
____ forms the body and tail of the panvreas
____ forms the head of the pancreas
Dorsal
Ventral
The main pancreatic duct is formed by?
Accessory pancreatic duct is formed by?
Distal duct of the dorsal pancreatic bud and ventral duct of the pancreatic bud
Proximal duct of the dorsal pancreatic bud
The mid gut communicate with the yolk sac through
Vitelline duct
Midgut herniation occurs@___ week
Midgut retraction occurs@___ week
Midgut rotation occurs@___ week
Her–week 6( midgut loop elongates and abdominal cavity becomes small and part of d intestine herniate)
Retra– week 10 ( abdominal cavity becomes enlarged and the herniated intestine becomes normal)
Rota– 2 parts = week 6( 90 anticlockwise rotation caecum shift to left), week10 180 anticlockwise rotation caecum positioned normally)
Atresias of the the duodenum causes?
Incomplete recanlization
Atresias of the the juodenum, ileum, colon causes?
Arterial occlusion unlike duodenum
Clockwise rotation of the gut causes?
Situs inversus
Volvulus
The rotation of the loop around the superior mesenteric artery
Distal 1/3 of the transverse colon, decending colon and sigmoid colon arises from?
Cranial end of the hindgut
The Essenteric nervous system is made up of?
Myenteric( auerbach) and sub mucosal plexus
The myenteric NS lies between____ and ____
Used in parasltatic movements(eg stomach)
Regulates?
Circular and longitudinal muscle
Motility
Sub mucosal plexus lies between _____
And regulates?
circular and muscularis mucosa
Electrolytes and water transport
Gland secretion
Blood flow
____ separate the hindgut from the allantouis
Urogenital septum
Urogenital setum if formed from?
It’s formed from the mesoderm in the junction between the yolk sac and connecting stalk
The urogenital saptum has 2 folds namely?
Superior, midline fold of the Tournuex
And paired lateral Rathke fold
@ ____ week the anal opening is closed
@___ week the anal opening is recanalyzed
8th week
9th week
The terminal board of the anal canal is of ___ origin?
And is supplied by ____ artery
Ectoderm
Inferior rectal artery
