Embryology Of Foregut Flashcards by Iseoluwa Ojo

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

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In the anterior part, the endoderm forms the _______; in the tail region, it forms the _______.

foregut

hindgut

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The part between foregut and hindgut is the ______.

midgut

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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.

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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

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Extent of Foregut:

•Foregut starts from the Oral cavity and terminates at the level of ________

Ampulla of Vater

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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

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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

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The foregut derivatives except the _______, ___________ and most of ______ are supplied by the _________- the artery of the foregut

pharynx

lower respiratory tract

esophagus

Celiac trunk

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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

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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

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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

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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

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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

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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

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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

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Stomach

During next 2 weeks:
•The ______ border grows much faster and forms the _____ curvature
•The ___ border forms the ____ curvature

dorsal

greater

ventral

lesser

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As stomach enlarges, it slowly rotates ___ degrees, ___wise around its _________ axis

clock

Longitudinal

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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

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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

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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

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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

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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

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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

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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

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

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