Anatomy of Small Bowel

Question 1

Where does the duodenum begin?

Answer 1

Pyloric sphincter

Question 2

What does the duodenum receive and from what?

Answer 2

Chyme

From stomach

Question 3

What neutralizes the acidic chyme going into the duodenum?

Answer 3

Alkaline mucous released by Brunner’s gland in the sub-mucosa

Question 4

Pancreatic secretions?

Answer 4

Digestive enzymes from acinar cells

-Alkaline fluid to neutralize

Question 5

What do bile salts do?

Answer 5

Break down large lipids for attack by TAG lipases

Question 6

Where are the jejunum and ileum in the peritoneum?

Answer 6

Intraperitoneal

Question 7

What vertebrae does the jejunum begin at?

Answer 7

L2

Question 8

What/where are Peyer’s patches?

Answer 8

Ileum

Aggregates of lymphoid tissue

Question 9

Way to remember order of gut organs?

Answer 9

DJ Ileum

Question 10

What increases SA of small bowel?

Answer 10

Large circular folds of the villi wall
Villi
Microvilli

Question 11

Lipid absorption in the small bowel. Sequence of events?

Answer 11

• Ingested lipids are broken down by gastric enzymes & dd secretions (increasing SA)
• Form emulsion droplets
• CCK initiates release of TAG lipases (which hydrolyses the TAG)
• Small chain fatty acids will move into capillaries (diffusion)
• Large chain FA incorporated into chylomicrons
• These are released into lymph vessels by exocytosis

Question 12

What is water balance driven by?

Answer 12

Solutes (primarily sodium)

Question 13

Fat soluble vitamins?

Answer 13

Vit A, D, E, K

Question 14

Water soluble vitamins?

Answer 14

Vit B, C, H

Question 15

What is segmentation?

Answer 15

Occurs after meals, alternating contraction and relaxation of segments of circular muscle. Initiated by intestinal pacemaker cells

Question 16

What is peristalsis driven by?

Answer 16

MCC

Question 17

What vertebrae does coeliac trunk arise at?

Answer 17

T12

Question 18

How many branches of coeliac trunk? and what does it supply?

Answer 18

3

Foregut organs

Question 19

What is the marginal artery of Drummond?

Answer 19

Anastamosis between IMA and SMA

It can help prevent intestinal ischaemia

Question 20

Lymph vessels?

Answer 20

Celiac nodes
Superior mesenteric
Inferior mesenteric
Lumbar nodes

Question 21

Where does lymph drain to?

Answer 21

Left venous angle via thoracic duct or the right.

Question 22

What drains blood from hind gut?

Answer 22

Inferior mesenteric vein

Question 23

What part of the gut does the splenic vein drain blood form?

Answer 23

Foregut

Question 24

What drains blood form the midgut?

Answer 24

Superior mesenteric vein

Question 25

Where do all of the -gut veins drain to?

Answer 25

Hepatic portal Vein
then
IVC (through liver)