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

Question 1

Why doesn’t a person’s “guts” spill out onto the floor when they are attacked and eviscerated by a ninja?

Answer 1

The midgut and hindgut are tethered by the dorsal mesogastrum.

Question 2

The midgut and the hindgut leave the abdomen during what week of development? When do they return? Why do they leave in the first place?

Answer 2

Leave wk 5. Return wk 10. Leave to give abdomen time to enlarge and to allow them to move around so that they can rotate 270 degrees.

Question 3

What are the arterial branches of the Superior Mesogastric artery?

Answer 3

The superior mesogastric artery branches off the abdominal aorta to supply the midgut. Its branches are:
Jejunal a 
Ileal a.
Ileocolic a. 
Appendicular a. 
Right colic a. 
Middle colic a.

Question 4

What area does the Jejunal artery supply?

Answer 4

Jujenum

Question 5

What area does the Ileal artery supply?

Answer 5

Ileum

Question 6

What area does the Ileocolic artery supply?

Answer 6

Cecum, ileum, vermiform appendix, ascending colon.

Question 7

What area does the Appendicular artery supply?

Answer 7

Appendix

Question 8

What area does the Right colic artery supply?

Answer 8

Ascending colon

Question 9

What area does the Middle colic artery supply?

Answer 9

Transverse colon

Question 10

Why is it important to know the branches of the SMA and what organs they supply?

Answer 10

It tells the surgeon where to resect, as resection is done to include everything perfused by the artery and veins where the primary tumor is located

Question 11

What is the fuel, that also happens to be the most abundant amino acid found in the blood, used by enterocytes?

Answer 11

Glutamine

Question 12

What fuel do colonocytes (cells of the large intestine/colon) use?

Answer 12

Short-chained fatty acids

Question 13

What structures run in the mesentery?

Answer 13

Arteries, veins and lymphatic structures

Question 14

Where does the mesentary insert?

Answer 14

The posterior aspect of the hollow viscera

Question 15

How is the surface area of the small intestine increased millions if not billions of times from what it would be if it was just a PVC pipe?

Answer 15

A remarkable, fractal, system of plica, villi, and microvilli. Plica circulares are large circular folds created by contraction of the muscularis mucosa. Villi are folds of mucosa covered by a single layer of enterocytes, the main functional cell of the intestines. Microvilli are projections of enterocyte cell membranes into the lumen, also called the brush border.

Question 16

Why is it bad sometimes for lymphatic drainage if a person gets stabled in the left neck?

Answer 16

The thoracic duct empties into the junction of the left subclavian and the internal carotid vein.

Question 17

What structure in a villi marks the beginning of the lymphatic collection system in the GI tract?

Answer 17

The lacteal