Digestive System Flashcards Preview

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Flashcards in Digestive System Deck (34):
1

List the structures of the GI tract in order starting with the stomach

Stomach, Duodenum, Jejunum, Ileum, Cecum, Ascending colon, Transverse colon, Descending colon, Sigmoid colon, Rectum, Anus

2

What are the three developmental sections of the GI tract?

Foregut, Midgut, Hindgut

3

Name the vessel off the aorta for each embryonic GI section

Foregut - Celiac trunk, Midgut - Superior mesenteric artery, Hindgut - Inferior mesenteric artery

4

What is the farthest structure into the GI tract which is innervated by the vagus nerve?

The distal portion of the transverse colon

5

From what embryonic GI structure is the duodenum derived?

Foregut and midgut

6

What is the arterial supply of the duodenum?

Celiac and superior mesenteric arteries

7

Does the duodenum occupy an intraperitoneal or retroperitoneal position?

Both. The 1st portion is intraperitoneal, the 2nd through 4th portions are retroperitoneal

8

Where are the dorsal and ventral pancreatic ducts when they fuse?

At the foregut-midgut junction

9

When the dorsal pancreatic duct persists what is it called?

The accessory pancreatic duct

10

What is an annular pancreas, what causes it, and what might it cause?

When the dorsal and ventral pancreas buds dont properly fuse. It can happen when the two buds migrate opposite directions, and it can cause duodenal stensosis (ventral pancreas sits right on duodenum)

11

What happens to the duodenal lumen during development?

It is obliterated in the 5th or 6th week and recanalized by the end of the 8th week

12

What is the difference between duodenal stenosis and duodenal atresia

Stenosis is a partial occlusion, atresia is a complete occlusion

13

Where are duodenal stenosis and duodenal atresia respectively most common?

Stenosis - 3rd and 4th portions of duodenum, Atresia - 2nd or 3rd portion of duodenum

14

Why is polyhydramnios present with duodenal atresia?

Because the embryo normally swallows amniotic fluid, but cannot if the duodenum is completely occluded

15

What do we typically look for when checking for possible duodenal atresia?

A double bubble appearence on ultrasound. Air will be present in both stomach and duodenum.

16

Invasion of the caudal portion of the septum transversum by the liver bud creates what structure?

The ventral mesentery

17

What are the derivatives of the ventral mesentery?

Falciform ligament, lesser omentum (divided into hepatogastric ligament to left and hepatoduodenal ligament to right)

18

What are the derivatives of the midgut?

Duodenum (some of 2nd portion, all of 3rd and 4th portion), Jejunum, Ileum, Cecum, Appendix, Ascending Colon, Two thirds of Transverse colon

19

When does umbilical herniation start and when does it return?

6th week to 10th week

20

Omphalocele

An abdominal wall defect in which the intestines, liver, and occasionally other organs remain outside abdomen

21

Gastroschisis

Congenital abdominal wall defect in which the intestines and sometimes other organs develop outside the fetal abdomen through an opening in the abdominal wall

22

Midgut rotations

A 90 degree CCW rotation while in cord around axis of SMA, and a 180 degree CCW rotation during reduction of hernia

23

Are each of the following fused or mobile, ascending colon, descending colon, transverse colon

Ascending and Descending are fused (to pos abdominal wall), Transverse has some mobility (fuses with pos wall of greater omentum)

24

Volvulus

A twisted intestine, may compromise blood supply

25

Left sided colon

When the gut rotates 90 degrees cw instead of ccw during development

26

What most likely causes gut atresias and stenoses

Vascular accidents

27

Meckels (Ileal) Diverticulum

Failure of vitelline duct to degenerate completely (can cause ulceration, bleeding, perforation)

28

What separates the allantois and hindgut?

Urorectal septum

29

What are the two divisions of the cloacal chamber?

Rectum and urogenital sinus

30

What are four conditions that may arise from abnormal hindgut development?

Persistent cloaca, anal stenosis, fistulas of various types, rectal atresia

31

Two types of hindgut fistulas

Urorectal fistula (connects distal hindgut to urinary system) and Rectovaginal fistula (connects rectum to vagina)

32

What might be one cause of rectal stenosis

Failure of neural crest cells to migrate and bring innervation to distal hindgut (no innervation will cause stenosis). This situation can cause congenital megacolon (Hirschsprung disease)

33

What is the primary concern regarding malrotation of the gut during physiologic herniation?

A malrotation may lead to a kinked superior mesentary artery

34

What is a quick way to recognize a malrotation of gut herniation?

A transverse colon behind the duodenum (normally the transverse colon will be anterior to the duodenum)

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