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Flashcards in GI Deck (187)
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What is derived from the foregut?
Midgut?
Hindgut?

Foregut - Pharynx to duodenum, liver, gallbladder, pancreas
Midgut - Duodenum to transverse colon
Hindgut - Distal transverse colon to rectum

1

What is gastroschisis?

Congenital malformation of the anterior abdominal wall causing extrusion of abdominal contents.
Not covered by peritoneum

2

What is an omphalocele?

Failure of intestines to return to body cavity after herniation into the umbilical cord. Covered by peritoneum

3

What causes intestinal atresia?

Duodenal atresia - failure to recanalize
Jejunal, ileal, colonic atresia - vascular accident in-utero

Vascular accident can cause apple peel syndrome where distal atrophic gut is wrapped around an artery.

4

When does midgut rotation occur?

6th week --> midgut herniates through umbilical ring

10th week --> abdominal cavity is large enough & midgut returns to it & rotates around SMA

Failure can cause malrotation of midgut or omphalocele

5

What are the possible types of tracheoesophageal abnormalities?
Which is most common?

Most common is EA with distal TEF

Others:
Pure EA
Pure TEF (H-type; fistula present but esophagus still patent)

6

What is seen with EA+TEF?

Drooling
Choking with first feeding
Cyanosis (laryngospasm to prevent reflux aspiration)
Air in the stomach on CXR
Failure to pass NG tube into stomach

7

What can result from malformation of the pancreas?

Annular pancreas - ventral pancreatic bud encircles 2nd part of duodenum & may cause narrowing. Due to failure of migration.

Pancreas divisum - Common; dorsal & ventral buds fail to fuse so that most pancreatic acini drain to minor sphincter. Predisposes to chronic pancreatitis.

8

From where does the spleen arise?

Arises from mesoderm but is supplied by foregut (celiac artery)

The other gut structures are all endodermal.

9

What are the retroperitoneal structures?

SAD PUCKER

Suprarenal glands
Aorta & IVC
Duodenum (2nd & 3rd parts)
Pancreas (except tail)
Ureters
Colon (ascending & descending)
Kidneys
Esophagus (lower 2/3)
Rectum (lower 2/3)

10

What is the falciform ligament?

Connects the liver to the anterior abdominal wall
Contains ligamentum teres (derivative of fetal umbilical vein)

11

What ligament contains the portal triad?

Hepatoduodenal ligament

Portal triad = hepatic artery, portal vein, common bile duct

12

What is the difference between an erosion and an ulcer?

Erosion = mucosa only

Ulcer = submucosa or deeper

13

What is the frequency of electrical rhythm along the GI tract?

Stomach = 3 waves/min

Duodenum = 12 waves/min

Ileum = 8 waves/min

14

What are the layers of the gut wall?

1) Mucosa (epithelium, lamina propria, muscularis mucosa)
2) Submucosa (includes Submucosal/Meissner's plexus)
3) Muscularis externa (includes Myenteric/Auerbach's plexus)
4) Serosa (intraperitoneal) or Adventitia (retroperitoneal)

15

What is the duodenum composed of histologically?

Villi & microvilli
Brunner's glands (unique to duodenum; HCO3-)
Crypts of Lieberkuhn (throughout small & large intestine)

16

What is the histology of the ileum?

Peyer's patches (unique to ileum)
Largest # of goblet cells in SI
Plicae circularis (along with jejunum)
Crypts of Lieberkuhn

17

What can result from failure of the vitelline (omphalomesenteric) duct to obliterate?
When should it obliterate?

Meckel diverticulum
Persistent vitelline duct
Vitelline cyst
Vitelline sinus

Should obliterate during the 7th week

18

What does an acid fast stain bind to?

Mycolic acid (TB, Nocardia)

19

What can cause papillary necrosis?

Sickle cell disease or trait
Analgesic use
Diabetes
Acute pyelonephritis

20

When is a child at risk for hemolytic disease of the newborn?

Anti-A or Anti-B Ig's are formed early in life. If a mother is A or B, she will form IgM (cannot cross placenta). If she is O, she will form IgG (can cross placenta). Thus, even her first child is at risk.

Mothers must be inoculated (with the first birth) against Rh. Subsequent births are at risk.

21

What is the difference in mechanism between unfractionated heparin and LMW heparin?

Unfractionated heparin binds Xa & IIa equally

LMW heparin preferentially binds Xa

*Antithrombin is needed in both cases to form the ternary inactive complex (heparin, AT, Xa/IIa)

22

What is the function of human Placental Lactogen (hPL)?

Insulin resistance --> fetus gets more of the glucose
^Lipolysis, proteolysis --> energy for both mom & fetus

hPL levels rise throughout gestation to support a growing fetus

23

What can be seen as a side effect of massive amounts of blood transfusions?

If a patient gets an entire body content of blood (5L) in under 24h, citrate from the blood products (additive) can accumulate and chelate the blood calcium causing hypocalcemia.

24

Where do the nitrogen atoms in urea come from?

Free NH3 (alanine cycle)
Aspartate (added into the urea cycle)

25

How id carbamoyl phosphate synthetase I regulated?

Rate-limiting enzyme in the urea cycle

It is activated by N-acetylglutamate

26

What physical exam findings are more specific for iron deficiency anemia?

Dysphagia
Spoon nails (koilonychia)

27

What growth factors are responsible for angiogenesis?

FGF
VEGF

This is true both in granulation tissue & in tumorgenesis

28

What is the receptor for rabies virus in the body?

Nicotinic ACh receptor

29

What is the cellular receptor for CMV?

Cellular integrins