02b: GI Anatomy and Embryology

Question 1

Mesentary, in general, is (X) that carries (Y) to/from (Z).

Answer 1

X = double layer of peritoneum
Y = nerves, vessels and lymphatics
Z = organs

Question 2

THE mesentery is:

Answer 2

mesentery that anchors jejunum and ileum to posterior body wall

Question 3

Peritoneal ligaments are (X) that (Y).

Answer 3

X = folds/condensations of peritoneum
Y = anchor organ to body wall or to another organ

Question 4

Intraperitoneal organs (are/are not) covered in peritoneum. What, if anything, attaches them to body wall?

Answer 4

Are;

Mesentary suspends them from body wall

Question 5

What are retroperitoneal organs?

Answer 5

Organs that remain posterior to peritoneal sac

Question 6

Secondarily retroperitoneal organs develop initially as (X) and then become (Y).

Answer 6

X = intraperitoneal organs
Y = compressed against body wall

Question 7

What separates secondarily retroperitoneal organs from body wall?

Answer 7

A bloodless plane

Question 8

The urogenital organs are (retroperitoneal/intraperitoneal/secondarily retro).

Answer 8

Retroperitoneal

Question 9

The major vessels, like aorta and IVC, are (retroperitoneal/intraperitoneal/secondarily retro).

Answer 9

Retroperitoneal

Question 10

Development of mesenteries in embryo, such as (X), occurs during which process?

Answer 10

X = dorsal mesentary

Lateral folding

Question 11

During embryonic development: Cranially, a (ventral/dorsal) mesentery arises from (X). (X) eventually becomes which structure?

Answer 11

Ventral;
X = septum transversum

Becomes diaphragm

Question 12

Adult remnants of ventral mesentery. Star the one attached to (anterior/posterior) body wall.

Answer 12

1. Falciform ligament* (anterior body wall)

2. Lesser omentum

Question 13

What’s the key distinguishing characteristics between foregut, midgut, hindgut?

Answer 13

The arteries that supply them

Question 14

List derivatives of foregut.

Answer 14

1. Stomach
2. Liver
3. Gallbladder
4. Pancreas
5. Duodenum (parts 1 and 2)

Question 15

List derivatives of midgut.

Answer 15

1. Small intestine (duodenum parts 3 and 4, jejunum, ileum)

2. Large intestine (cecum, appendix, ascending colon, first half of transverse colon)

Question 16

List derivatives of hindgut.

Answer 16

1. Large intestine (second half of transverse colon, descending colon, sigmoid colon)
2. Rectum

Question 17

(X) artery supplies foregut.

Answer 17

X = celiac trunk

Question 18

(X) artery supplies midgut.

Answer 18

X = superior mesenteric

Question 19

(X) artery supplies hindgut.

Answer 19

X = inferior mesenteric

Question 20

In development of stomach, (X) border grows faster and the tube rotates (Y) degrees in (clockwise/counter-clockwise) direction.

Answer 20

X = dorsal
Y = 90

clockwise

Question 21

Lesser sac, aka (X), is part of (Y) and lies dorsal to (Z).

Answer 21

X = omental bursa
Y = peritoneal cavity
Z = stomach

Question 22

What’s the omental foramen?

Answer 22

Opening from general peritoneal cavity into lesser sac

Question 23

Name some additional names for omental foramen.

Answer 23

1. Forman of Winslow

2. Epiploic foramen

Question 24

Anterior wall of lesser sac is created by:

Answer 24

1. Stomach

2. Lesser omentum

Question 25

With embryonic folding and relocation of ventral/dorsal mesogastrium, which (arteries/veins/nerves) also change position?

Answer 25

1. Right vagus nerve (relocates posteriorly) | 2. Left vagus nerve (relocates anteriorly)

Question 26

As the foregut rotates, (X) grows extensively, resulting in long sheet of (Y) that hangs from (Z). What structure does this become?

Answer 26

``` X = dorsal mesogastrium Y = mesentery Z = greater curvature of stomach ``` Greater omentum

Question 27

T/F: Greater omentum is still mesentery, with two layers of peritoneum.

Answer 27

Partially false - still mesentery, but 4 layers of peritoneum

Question 28

List functions of greater omentum

Answer 28

1. Adheres to adjacent structures 2. Immune 3. High absorptive capacity 4. Promotes healing

Question 29

Elaborate on immune function of (greater/lesser) omentum.

Answer 29

Greater; Primary site via which macrophages/neutrophils enter peritoneal cavity

Question 30

Which key structures develop in foregut with the duodenum?

Answer 30

1. Pancreas 2. Liver 3. Gallbladder

Question 31

There are (X) parts of duodenum. Which are intraperitoneal?

Answer 31

X = 4 First (superior) and fourth (ascending) Second (descending) and third (horizontal) are secondarily retroperitoneal

Question 32

Uncinate process of (X) is a small lobe stemming from (head/body).

Answer 32

X = pancreas | Head

Question 33

At head of pancreas, the pancreatic duct joints (X) from (Y), and both go to (Z).

Answer 33

``` X = common bile duct Y = liver Z = duodenum ```

Question 34

C-shaped of duodenum wraps around:

Answer 34

Head of pancreas

Question 35

Pancreas is (intraperitoneal/retroperitoneal/secondarily retro).

Answer 35

Secondarily retroperitoneal

Question 36

(X) vessels pass vertically and (anteriorly/posteriorly) between which processes of pancreas?

Answer 36

X = superior mesenteric Posteriorly; Between neck and uncinate process

Question 37

Liver is in contact with which remnant of ventral mesogastrium?

Answer 37

Both: 1. Falciform ligament 2. Lesser omentum

Question 38

Which two (X) technically make up the lesser omentum?

Answer 38

X = ligaments 1. Hepatoduodenal 2. Hepatogastric

Question 39

The portal triad consists of (X) and travels with (Y).

Answer 39

``` X = portal vein, common hepatic artery, bile duct Y = hepatoduodenal ligament ```

Question 40

There are anastamoses along (greater/lesser) curvature of stomach. Which arteries involved?

Answer 40

Both; Lesser: Left and right gastric Greater: Left and right gastro-omental

Question 41

Celiac trunk main branches.

Answer 41

1. Left gastric artery 2. Splenic artery 3. Common hepatic artery

Question 42

Short gastric arteries branch off of:

Answer 42

Splenic artery

Question 43

Common hepatic artery gives off which branches?

Answer 43

1. Proper hepatic artery | 2. Gastroduodenal artery

Question 44

Right gastro-omental artery branches off of:

Answer 44

Gastroduodenal artery

Question 45

Right gastric artery branches off of:

Answer 45

Proper hepatic artery

Question 46

Left gastro-omental artery branches off of:

Answer 46

Splenic artery

Question 47

During midgut development, (X) herniate into (Y).

Answer 47

``` X = intestines Y = umbilical cord ```

Question 48

The first (X) degrees of rotation of midgut occurs during herniation. Once the loops are drawn back into body, another (Y) degrees of rotation occur.

Answer 48

``` X = 90 Y = 180 ```

Question 49

Total degrees of rotation in midgut is (X) degrees (clockwise/counterclockwise).

Answer 49

X = 270 | Counter-clockwise

Question 50

Ascending colon is (intraperitoneal/retroperitoneal/secondarily retro).

Answer 50

Secondarily retro

Question 51

Transverse colon is (intraperitoneal/retroperitoneal/secondarily retro).

Answer 51

Intraperitoneal

Question 52

Descending colon is (intraperitoneal/retroperitoneal/secondarily retro).

Answer 52

Secondarily retro

Question 53

Together, jejunum and ilium are (X) long and distinguished by (Y).

Answer 53

``` X = 6-7 meters Y = physical properties (walls, mesentery, etc.) ```

Question 54

The (jejunum/ilium) has thicker walls.

Answer 54

Jejunum

Question 55

The (jejunum/ilium) has less fat in mesentery.

Answer 55

Jejunum

Question 56

The (jejunum/ilium) has shorter vasa recta.

Answer 56

Ilium

Question 57

List branches off SMA:

Answer 57

1. Inferior pancreaticduodenal 2. Jejunal and ileal branches 3. Ileocolic (with cecal and appendicular branches) 4. Right and middle colic

Question 58

Which branch off SMA forms anastamosis with branch off celiac trunk?

Answer 58

Inferior pancreaticduodenal (off SMA) with superior pancreaticduodenal (off gastroduodenal artery)

Question 59

List branches off IMA.

Answer 59

1. Left colic 2. Sigmoid 3. Superior rectal

Question 60

(Left/right) infracolic space drains out of rectum.

Answer 60

Left

Question 61

(Left/right) paracolic gutter drains out of rectum.

Answer 61

Both

Question 62

Supine person will have fluid accumulation in which area(s) primarily?

Answer 62

1. Hepatorenal (Morrison) pouch | 2. Rectovesical/rectouterine pouch (of Douglas)