Embryology Of Foregut Flashcards
endodermal germ layer.
This germ layer covers the (ventral or Dorsal?) surface of the embryo and forms the (roof or floor?) of the yolk sac.
With development and growth of the brain vesicles, the embryonic disc begins to fold ________________. The folding is most pronounced in the regions of the ____ and _____, where they form head and tail fold
Ventral
Roof
cephalocaudally
head and tail
In the anterior part, the endoderm forms the _______; in the tail region, it forms the _______.
foregut
hindgut
The part between foregut and hindgut is the ______.
midgut
The midgut temporarily communicates with the yolk sac by way of a (broad or narrow?)?stalk, the _____
•At its cephalic end, the foregut is temporarily bounded by an ectodermal-endodermal membrane called the ________
Broad
vitelline duct
buccopharyngeal membrane.
In the ___ week, the buccopharyngeal membrane ruptures, establishing an open connection between the _____ and the primitive gut
•The hindgut also terminates temporarily at an ______________ membrane- the ____ membrane, which breaks down in the ___ week to create the opening for the ____.
4th
amniotic cavity
ectodermal-endodermal
cloacal
7th
anus
Extent of Foregut:
•Foregut starts from the Oral cavity and terminates at the level of ________
Ampulla of Vater
By the end of the first month: The \_\_\_\_\_\_\_ is visible, \_\_\_\_\_\_\_\_ has begun to bud Connection of the midgut to the yolk sac is \_\_\_\_\_\_\_\_\_ to a \_\_\_\_\_\_
stomach bulge
Dorsal pancreas
reduced to a yolk stalk
A respiratory diverticulum develops from the (roof or floor?) of the foregut, divides the foregut into two parts:
•Part cranial to diverticulum - ______
•Part caudal to diverticulum -_______
Floor
primitive pharynx
foregut proper
The foregut derivatives except the _______, ___________ and most of ______ are supplied by the _________- the artery of the foregut
pharynx
lower respiratory tract
esophagus
Celiac trunk
Development of the Esophagus
•Esophagus develops from the foregut immediately (cranial or caudal?) to the primitive pharynx
The _________________ separates it from the developing trachea
Caudal
tracheo-esophageal septum
Initially (short or long?) in length, esophagus elongates (slowly or rapidly?) due to growth and _____ of ____ and ____
•Reaches its final relative length by ___ week
Short
Rapidly
descent of heart and lungs
7th
The epithelial cells of the esophagus proliferate and obliterate the lumen (partly or completely) but temporarily
Recanalization normally occurs by ____________ period (___ wk)
Failure of proper recanalization leads to ________ of the ______ (stenosis)
the end of the embryonic
8th
narrowing of the lumen
Esophagus
Epithelium & glands:
•Derived from ___derm
Striated muscles (mainly in the superior third): •Derived from the \_\_\_\_\_\_ in the \_\_\_\_\_\_
Smooth muscles (mainly in the inferior third): •Derived from the surrounding \_\_\_\_\_\_\_\_
endo
Mesenchyme ; caudal pharyngeal aches
splanchnic mesoderm
Congenital malformations of Esophagus
•Errors in forming the esophagotracheal septa and/or re-canalization lead to __________ and/or ____________, respectively.
Re-canalization –errors in this process lead to esophageal _______
tracheoesophageal fistulas
esophageal atresia
stenosis
Atresia of Esophagus prevents the normal passage of amniotic fluid into the ______ leading to the accumulation of excess fluid in the amniotic sac (_________)
Short esophagus resulting in _______
intestinal tract
Polyhydroamnios
hiatal hernia
Development of the Stomach
•In the middle of the ____ week, a ___________ appears in the (cranial or caudal?) part of the foregut (indicating site of future stomach)
•This dilatation (oriented in the midline), enlarges and broadens _____
4th
fusiform dilatation
Caudal
ventral dorsally
Stomach
During next 2 weeks:
•The ______ border grows much faster and forms the _____ curvature
•The ___ border forms the ____ curvature
dorsal
greater
ventral
lesser
As stomach enlarges, it slowly rotates ___ degrees, ___wise around its _________ axis
90
clock
Longitudinal
As a result of the stomach’s rotation,
- The ventral border moves to the ___ and the dorsal border to the ____
- The original left side becomes the ______ surface and the original right side becomes the ______ surface
right
left
ventral
dorsal
Initially the two ends of the stomach lie in the midline. During rotation:
•the cranial end moves to the ___ and slightly ____
•the caudal end moves to the ____ and _____
left; inferiorly
right; superiorly
Formation of the Lesser sac/Omental Bursa
•During its dev, the stomach is suspended in the midline with the help of ____-layered mesenteries (_______),
double
mesogastrium
The Dorsal mesogastrium connects stomach to the _____ body wall.
•The Ventral mesogastrium attaches the gut tube to the _____ abdominal wall
•Rotation around the longitudinal axis pulls the ‘dorsal mesogastrium’ to the ____.
•This move leads to the formation of _______
post/dorsal
ant
left
OMENTAL bursa
Formation of Greater & Lesser Omenta
•With the rotation of stomach, the ____ curvature along with the attached ___ mesogastrium becomes the ‘Greater Omentum’
•While the _____ mesogastrium lying between the _____ curvature of stomach & the (superior or inferior?) surface of liver- ‘Lesser Omentum’
greater; dorsal
ventral; lesser; inferior
Stomach Abnormalities
- Pyloric stenosis occurs when ____ of the stomach in the region of the pylorus _______.
- There is an extreme _____ of the pyloric lumen, passage of food is obstructed- severe vomiting.
musculature; hypertrophies
narrowing
Pyloric stenosis begins in post fetal life
T/F
F
believed to develop during fetal life.
malformations of the stomach, such as duplications are common
T/F.
F
rare
Pyloric stenosis
Characterized by _______ (aka “_____”), non-bilious vomiting _____. after feeding (when ________ would occur).
very forceful
projectile
~1hr
pyloric emptying
Hypertrophied sphincter can often be palpated as a spherical nodule; peristalsis of the sphincter seen/felt under the skin.
T/F
T
Pyloric Stenosis is due to an error in re-canalization.
T/F
F
Stenosis is due to overproliferation / hypertrophy of pyloric sphincter… NOT an error in re-canalization.
Pyloric stenosis is More common in ____ than ______, so most likely has a genetic basis which is as yet undetermined.
males
females
Development of the Duodenum
Duodenum begins to develop early in ___ week, from the (cranial or caudal?) part of the foregut and (cranial or caudal?) part of the midgut
•Grows rapidly, forms a __-shaped loop that projects (ventrally or dorsally?)
4th
Caudal
Cranial
C
Ventrally
DUODENUM
Rotation of stomach pulls the duodenum to the ____ and (ventrally or dorsally?) , bringing it in a ____-peritoneal position
During _____ weeks, its lumen obliterates due to proliferation of epithelial cells
•Recanalization is complete by the end of embryonic period
•Most of the (ventral or Dorsal?)?mesentery disappears by this time
right
Dorsally
retro
5-6th
Ventral
Congenital abnormalities of duodenum
•Duodenal stenosis-incomplete recanalization involves ____ and ____ parts of duodenum
•Duodenal atresia- complete occlusion of lumen involves ____ and ___ parts of duodenum
•Clinical presentation is ____ vomiting in infants
•“________” sign on X-ray or USS
3rd & 4th
2nd & 3rd
bilous
Double bubble
Development of the Liver
•Liver appears in ____ week, as a (ventral or Dorsal?) bud called __________, from the (cranial or caudal?) part of the foregut
The bud grows into the _______ and divides into two parts:
•Larger (cranial or caudal?) part - primordium of ____;
•Smaller (cranial or caudal?) part- ______ and ______
4th
ventral
hepatic diverticulum
Caudal
septum transversum
Cranial; liver
Caudal; gall bladder and cystic duct
Liver
The proliferating endodermal cells give rise to __________ and the epithelial linning of the ______ part of the biliary apparatus
The hepatic cords anastomose around the _____ derived from the ______
The liver grows rapidly and in __-__ weeks , fills a large part of the abdominal cavity
•By ___ week, the liver forms about __% of total body weight
interlacing cords of hepatocytes
intrahepatic
sinusoids; vitelline veins
5-10th
9th; 10
Initially the right and left lobes of the liver are of the same size, later ____ lobe grows larger
right
The hepatic cords and the epithelial lining of the intrahepatic portion of the biliary system are derived from ____derm
endo
The ___ tissue, hematopoeitic tissue and Kupffer cells are derived from the ______ of _____
fibrous;hematopoietic
mesenchyme of the septum transversum
The hepatic sinusoides derived from ______
Hematopoeisis begins during ___ week, giving ____ color to liver
The hepatic cells begins to form bile during the ____ week
vitelline veins
6th; dark
12th
Development of the Biliary Apparatus
•The small caudal part of the hepatic diverticulum becomes the ____, and the stalk of the diverticulum forms the _____
.
gall bladder
cystic duct
GALLBLADDER AND DUCT
The stalk connecting the hepatic & cystic ducts to the duodenum becomes the _____, and opens on the (ventral or Dorsal?) aspect of the duodenum originally
Later due to ________, the opening comes to lie (ventrally or dorsally?)
•The ducts become occluded initially, but are later canalized
•Bile formation commences about the ____ week,
bile duct
Ventral
rotation of duodenum
dorsally
12th
bile entering the duodenum gives a _____ color to the intestinal contents (_____)
dark green
meconium
Development of the Pancreas
•Pancreas begins to appear as ____, ___ and ___ , from the (cranial or caudal?) part of the foregut
•The _____ bud is larger, appears first and lies (cranial or caudal?) to the smaller ____ bud
two buds
dorsal and ventral
Caudal
dorsal
Cranial; ventral
PANCREAS
The rotation of stomach and duodenum carry the ventral bud (ventrally or dorsally?) along with the bile duct.
The ventral bud comes to lie (ant or post?) to the dorsal bud and later fuses with it and their ducts anastomose
Dorsally
Post
PANCREAS
The duct of ___ bud and (proximal or distal?) part of the duct of the ____ bud form the main pancreatic duct that opens on the _____ duodenal papilla
ventral
Distal
dorsal
major
PANCREAS
The (proximal or distal?) part of the duct of the _____ bud often persists as the accessory pancreatic duct that opens separately on the _____ duodenal papilla
Proximal
dorsal
minor
The _____ bud forms most of the pancreas
dorsal
The ____ bud gives rise to the uncinate process of the pancreas
ventral
The ventral bud gives rise to part of the head of the pancreas
T/F
T
Insulin production begins - _____week
•Glucagon ____ week
10th
15th
Derivatives of the Mesenteries of the Foregut
- Dorsal Mesoesophagus:____ of the ___
- Ventral Mesoesophagus: ____________
- Dorsal Mesogastrium:______ ligament, ______ ligament
Crura of the diaphragm
disappears completely
Lienorenal; Gastrosplenic
Derivatives of the Mesenteries of the Foregut
Ventral Mesogastrium:
•______
•___________
•_____________
Dorsal mesentery of the duodenum: persists in the proximal part (one inch) as _____ ligament
Ventral mesentery of the duodenum: ________
Lesser omentum
Visceral peritoneum of the liver
Falciform ligament of the liver
hepatoduodenal
disappears almost completely
Anomalies Related to the Development of the Liver & Gall Bladder
Variations in hepatic ducts, cystic and bile ducts are (common or rare?) and clinically significant
•_________ is the most common serious anomaly._______ develops soon after birth. If uncorrected surgically leads to death
common
Extrahepatic biliary atresia
Jaundice
Anomalies of liver are common
T/F
F
Rare
Anomalies Related to the Development of the Pancreas
- ______________
- _____pancreas
Accessory pancreatic tissue
Annular
bird beak deformity is associated with _______
Achalasia cardia
Failure of recannalization =______
Incomplete recannalization =_____
Atresia
Stenosis
Right and left triangular ligaments are derived from ?????
Ventral mesogastrium
Superior and inferior layers of coronary ligaments of the liver are derivatives of ????
Ventral mesogastrium
Ligamentum teres hepatis is derived from ____________
obliterated left umbilical vein
Duodenal diverticuli: They are seen along the (inner or outer?) border of the _____ and _____ part of the duodenum.
Inner
second and third
Shah
When
