Organ Systems II GI Anat Phys Embr Part III (RC)

Question 1

What happens if the gut does not rotate 270 degrees? What condition is a result?

Answer 1

Intestinal malrotation. Intestinal obstruction.

Question 2

What is the most common malformation of the GI tract? How does it form?

Answer 2

Meckel’s diverticulum. Results if the Vitelline duct does not obliterate.

Question 3

Why does Meckel’s sometimes bleed?

Answer 3

Has gastric tissue in it that responds to circulating blood gastrin and subsequently produces HCL, which erodes the intestinal wall.

Question 4

What are the characteristics of Meckel’s?

Answer 4

True congenital diverticulum. Small bulge (remnant of the Vitelline duct) in the small intestine at birth. On antimesenteric border of small bowel. Bleeding may not start until adulthood.

Question 5

What is the incidence of Meckel’s and what is the most common population group affected?

Answer 5

2% of overall population. More frequent in males.

Question 6

What is the #1 cause of painless bleeding in children?

Answer 6

Meckel’s

Question 7

What are the 4 conditions that can occur if the vitelline duct fails to completely close?

Answer 7

1. Meckel’s diverticulum
2. Vitelline cyst
3. Vitelline fistula
4. Abdominal closure prior to retraction of intestines

Question 8

What is intussusception?

Answer 8

Telescoping (invagination) of one segment of intestine into another

Question 9

What does it mean when it says that there is a “lead point” for intussusception?

Answer 9

Usually a swelling that leads the telescoping segment into the other (enlarged Peyer’s patches, lymphoma, Meckel’s)

Question 10

What is the most common lead point for intussusecption for a child? For an adult?

Answer 10

For children, the lead point is often a swollen lymph node, for an adult it is often a tumor

Question 11

What is the most common cause of small bowel obstruction? Large bowel obstruction?

Answer 11

Small bowel: Intra-abdominal adhesions

Large bowel: Cancer

Question 12

What are the branches of the inferior mesenteric artery?

Answer 12

Left colic a.
Superior rectal a.
Sigmoid branches

Question 13

What area(s) does the left colic artery supply?

Answer 13

Descending colon

Question 14

What area(s) does the superior rectal artery supply?

Answer 14

Rectum

Question 15

What area(s) do the sigmoid branches of the inferior mesenteric artery supply?

Answer 15

Lower part of the descending colon, the iliac colon, and the sigmoid or pelvic colon

Question 16

What is the function or consequence of Tenia Coli?

Answer 16

Being shorter than the underlying viscus, they create Haustra and attachment points for structures

Question 17

What are the divisions of the large intestine?

Answer 17

Ascending colon, transverse colon, descending colon, Sigmoid colon, Rectum, Anal canal

Question 18

Why is the sigmoid colon’s “floppiness” clinically important?

Answer 18

The sigmoid colon is floppy, so diseases there can appear to be on the right side since it can flip over to that side even though the sigmoid is on the left

Question 19

What is the underlying problem that causes Hirschsprung’s disease?

Answer 19

Failure of neural crest cells (ganglion cells) to progress in craniocaudal direction

Question 20

What layers are missing in “diverticular disease”?

Answer 20

Muscular layers

Question 21

How do a true and false diverticula differ?

Answer 21

C - Congenital, not acquired
R - Right side of colon
A - Asians, more common in
M - Muscular layers

Question 22

What is the difference between Diverticulosis and Diverticulitis?

Answer 22

Diverticulitis is inflammation, usually from infection, occurring in a diverticula
Diverticulosis is the presence of several diverticuli

Question 23

What structure is missing in the appendix?

Answer 23

Villi

Question 24

What are the characteristics of Crohn’s disease?

Answer 24

F - Fissures
L - Lesions (called skip lesions)
A - Anus, can involve
B - Bleeding absent 30% of the time

Question 25

What are the characteristics of Ulcerative colitis?

Answer 25

F - Fever
L - Loss of weight
A - Abdomenal pain
R - Rarely fistulas and strictures
D - Diarrhea, bloody (always)

UC always has bloody diarrhea, Crohn’s about 70% of the time

Question 26

What tissues/structures are involved in Ulcerative Colitis?

Answer 26

Involves mucosa and submucosa
Mucosal involvement contiguous
Spares anus

Question 27

What plexus do hemorrhoids form in?

Answer 27

Both the internal rectal venous plexus, and the inferior rectal venous plexus

Question 28

What plexus do suppositories take advantage of for absorption?

Answer 28

Internal rectal venous plexus