4.04a Small and Large Intestine I

Question 1

4 layers of the small intestine

Answer 1

Mucosa
Submucosa
Muscularis externa
Serosa

Question 2

Short tubular intestinal glands in the DUODENUM

Answer 2

Crypts of Lieberkuhn

Question 3

Mucous duodenal glands that is a distinctive feature of the UPPER DUODENUM

Answer 3

Brunner’s glands

Question 4

Outfoldings of the mucosa and submucosa that is extensive in the JEJUNUM

Answer 4

Plicae circulares (circular folds or valves of Kerckring)

Question 5

Aggregated lymphatic nodules that are a characteristic feature of the ILEUM

Answer 5

Peyer’s patches

Question 6

Differentiate MEISSNER’S PLEXUS and AUERBACH’S PLEXUS

Answer 6

Meissner: ganglion cells of the nerve plexus (submucosa)

Auerbach: ganglion cells of myenteric plexus (muscularis)

Question 7

Differentiate OMPHALOCELE AND GASTROSCHISIS

Answer 7

Omphalocele: defect at the site of the umbilical cord insertion; sac replaces umbilical cord

Gastroschisis: right side of the umbilical cord insertion; absence of sac

Question 8

Characteristics of Meckel diverticulum (hint: rule of 2s)

Answer 8

Present within 2 feet of the ileocecal valve

2 inches long

2x more common in males

Symptomatic by 2 y/o

Question 9

What makes Meckel diverticulum a true diverticulum?

Answer 9

Composed of 3 intestinal layers (mucosa, submucosa, muscularis)

Communicates with intestinal lumen

Question 10

What causes Hirschsprung disease?

Answer 10

Mutation in the tyrosine kinase receptor

Question 11

Differentiate the ff:

Volvulus
Hernias
Adhesions
Intussusception

Answer 11

Volvulus: twisting of the bowel around the mesenteric root

Hernia: weakness or defect in wall of peritoneal cavity leading to protrusion of serosa-lined pouch of peritoneum

Adhesions: fibrous bridges

Intussusception: segment of the intestines telescopes into the immediate distal segment

Question 12

Most common structures affected by volvulus (most to least common)

Answer 12

Sigmoid colon
Cecum
Small intestine
Stomach
Transverse colon

Question 13

Most common sites of acquired hernia

Answer 13

Inguinal canal
Femoral canal
Umbilicus
Site of surgical scar

Question 14

Differentiate INTUSSUSCEPTUM and INTUSSUSCIPENS

Answer 14

Intussusceptum: proximal segment constricted by peristalsis

Intussuscipens: immediate distal segment trapping the proximal segment

Question 15

Most common type of intussusception

Answer 15

Ileocolic intussusception

Question 16

Differentiate MUCOSAL, MURAL, and TRANSMURAL infarction.

Answer 16

Mucosal: hypoperfusion; mucosa

Mural: hypoperfusion; mucosa and submucosa

Transmural: obstruction; mucosa, submucosa, muscularis

Question 17

Site of greatest risk of transmural infarction

Answer 17

Splenic flexure

Question 18

Most common site of ANGIODYSPLASIA

Answer 18

Cecum and right colon

Question 19

Gluten hypersensitivity. What is the allele they carry?

Answer 19

Celiac disease. HLA-DQ2 or HLA-DQ8

Question 20

Screening test for celiac disease

Answer 20

IgA antibodies against tissue transglutaminase

adjunct: IgA anti-endomysial antibodies

Question 21

Characteristic findings in celiac disease

Answer 21

villous atrophy and crypt hyperplasia

Question 22

Patient is suspected of celiac disease. Where should biopsy be performed to confirm diagnosis? Why?

Answer 22

2nd part of duodenum or proximal jejunum. Exposed to highest concentration of gluten.

Question 23

Direction of changes and healing in celiac disease.

Answer 23

Changes proximal to distal

Heals distal to proximal

Question 24

Characteristic finding in Whipple disease

Answer 24

Foamy macrophages of the lamina propria of the small intestine (PAS-positive macrophages)

Question 25

Causative agent of Whipple disease

Answer 25

Tropheryma whippelii

Question 26

Triad of clinical features in Whipple disease

Answer 26

Diarrhea
Weight loss
Malabsorption

Question 27

Difference in change in villi in CELIAC DISEASE and WHIPPLE DISEASE

Answer 27

Celiac disease: villous atrophy

Whipple disease: villous expansion

Question 28

Most common cause of childhood diarrhea

Answer 28

Rotavirus

Question 29

Shigellosis mode of transmission

Answer 29

Fingers
Food
Feces
Flies