Division of the primitive gut from 1. Distal 1/3 of transverse colon to cloacal membrane 2. oropharyngeal membrane to liver 3. Liver to to distal 1/3 of transverse colon

1. Hindgut 2. Foregut 3. Midgut

Anatomy - Raj Flashcards by Tiffany Reid

Division of the primitive gut from

Distal 1/3 of transverse colon to cloacal membrane
oropharyngeal membrane to liver
Liver to to distal 1/3 of transverse colon

Hindgut
Foregut
Midgut

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Arterial supply of each gut division

Foregut: celiac
Midgut: SMA
Hindgut: IMA

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The inner lining of the primitive gut is ___. The muscular layer and outer peritoneal covering are derived from ___

Endoderm

Splanchnic mesoderm

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Dorsal mesentery subdivisions and ventral mesentery subdivisions:

Greater omentum (dorsal mesogastrium)
Mesoduodenum
Dorsal mesocolon
Mesentery proper
____
Lesser omentum
Falciform ligament

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Derivatives of the foregut

Esophagus
Stomach
Duodenum
Liver
Gall bladder
Pancreas

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Epithelium and glands of the esophagus are derived from __

Endoderm

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Innervation of the esophagus

Upper 2/3 is vagus

Lower 1/3 is splanchnic

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Esophageal atresia results from ___ and is often associated with ___. Clinical features include ___

Deviation of tracheoesophageal septum
Tracheoesophageal fistula
Constant salivation and freq. coughing

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Narrowing of the lumen of the esophagus.

May be due to incomplete recanalization

Esophageal stenosis

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Where the stomach is pulled into the thoracic cavity.

May be due to failure of the esophagus to lengthen

Congenital hiatal hernia

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The stomach appears as a ___ in week ____. It undergoes ___ which determines its final shape and position

Dilation of the foregut
4
2 rotations

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Rotations of the stomach:

Longitudinal axis- ant. becomes right, post. becomes left, left becomes ant. and right becomes post.
Anteroposterior axis- caudal part moves up and to the right, cephalic/cardiac part moves down and to the left

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Rotation of the stomach around the ____ axis displaces the dorsal mesogastrium to the left. This rotation also displaces the ___

Longitudinal

- ventral mesogastrium to the right

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The free edge of the lesser omentum connecting the duodenum and liver (____) contains what?

Hepatoduodenal ligament

-bile duct, portal v., hepatic a. proper

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Extreme narrowing of pyloric lumen due to hypertrophy of the circular muscle fibers.
Symptoms?

Pyloric stenosis
Common in infants
Projectile vomiting

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The duodenum is formed from the __

Importance?

Caudal part of foregut
Cephalic part of midgut

Supplied by both celiac and SMA

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As the stomach rotates, the duodenum ___

Forms a C-shaped loop and rotates to the right and becomes secondarily retroperitoneal (except the cap!)

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The liver bud appears in week ___

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The liver, gall bladder, and biliary duct system all along use from ___

The hepatic diverticulum (liver bud)

With the growth of the liver and gut, accompanied by the rotation of the stomach, the ventral mesentery becomes what?

Falciform ligament
Hepatoduodenal ligament
Hepatogastric ligament

The ____ become the portal v. which brings blood ___

Vitelline veins

From gut to liver

The ___ becomes the ligamentum venosum and the ___ becomes the round ligament of the liver

Ductus venosus (shunts blood being brought to the liver from umbilicus to IVC)
Umbilical v.

Due to failure of bile duct to recanalize. 
Jaundice soon after birth
Clay colored stools
Can be fatal
Requires surgery or liver transplant

Extrahepatic biliary atresia

The pancreas is formed by __

Dorsal and ventral pancreatic bud (2 outpouchings of the endodermal duodenum)

dorsal forms upper head, body, tail
ventral forms lower head, uncinate process

The main pancreatic duct (of Wirsung) is formed by___ Accessory pancreatic duct (of ___)

Distal part of dorsal duct Entire ventral duct -Santorini

T or F: the pancreas is intraperitoneal

F. Secondarily retroperitoneal

Results from growth of a bifid ventral pancreatic bud and one part of the ventral pancreatic bud migrates incorrectly in the opposite direction. The parts of the bifid ventral bud then fuse with the dorsal bud, the duodenum becomes surrounded by pancreatic tissue and causes obstruction of the duodenum

Annular pancreas

The spleen develops from __

Mesodermal proliferation between the 2 leaves of the dorsal mesogastrium

The spleen is attached to the posterior body wall (near the left kidney) by the ___ ligament and to the stomach by the ___ ligament. It is (intra/retroperitoneal)

Splenorenal (lienorenal) Gastrosplenic (gastrolienal) Intraperitoneal

The midgut forms the:

1. Duodenum, distal to bile duct 2. Jejunum 3. Ileum 4. Cecum 5. Appendix 6. Ascending colon 7. Proximal 2/3 of transverse colon

In the embryo the midgut is suspended dorsally by ___ and anteriorly is in communication with the ___ by way of the ___

A mesentery Yolk sac Vitelline duct or yolk stalk

Physiological (umbilical) herniation *First part to re-enter? Last?

During week 6 the ab organs enter the extraembryonic cavity in the umbilical cord *proximal jejunum, cecal bud

Rotation of the midgut

Axis = SMA | 270 degrees counterclockwise

Meckel's diverticulum

Disease of 2s | Outpocketing of the ileum due to persistence of the vitelline duct

Patent communication between ileum and umbilicus due to remaining vitelline duct. The umbilicus my discharge fecal matter

Umbilical fistula or vitelline fistula

Abnormal rotation of the gut can result in its twisting, compromising the blood supply

Volvulus

With malrotation, the gut only rotaries 90 degrees, rather than the normal ___. The colon and the cecum are the first part to return and end up on the ___ side of the abdomen

270 Left *left sided colon

Occurs when the primary loop rotates 90 degrees clockwise | *because of this ___

Reverse rotation of the intestinal loop | *transverse colon passes behind the duodenum

Failure of the bowel to return to the ab cavity from the physiological herniation. Results in herniation of the viscera through an enlarged umbilical ring

Omphalocele | *the viscera are covered by amnion

A protrusion of abdominal organs lateral to the umbilicus due to an abnormal closure of the body wall

Gastroschisis | *the viscera are not covered by peritoneum or amnion

The Hindgut forms the:

1. Distal 1/3 of transverse colon 2. Descending colon 3. Sigmoid colon 4. Rectum 5. Upper part of anal canal

A cavity lined by endoderm and covered centrally by surface ectoderm.

Cloaca

At the end of week __ the ___ ruptures forming an anal opening for the hindgut and a ventral opening for the urogenital sinus.

7 | Cloacal membrane

The junction between the endodermally and ectodermally derived parts of the anal canal

Pectinate line (just below anal columns)

Due to the absence of parasympathetic ganglion in the bowel wall -absence of peristalsis in that area Symptoms?

Congenital megacolon (Hirschsprung disease) -failure of infant to pass mesoconium within 24 hours, vomiting, distended abdomen

Occurs when the anal membrane fails to break down

Imperforate anus

Due to abnormalities in the formation of the cloaca and/or urorectal septum. Hindgut opens into urethra or vagina

Rectourethral and Rectovaginal fistulas