Small Intestine

Where does the small intestine extend to and from?

Pyloric orifice to ileocecal junction

How long is the small intestine?

7 meters

What does the small intestine absorb?

Nutrients

What does the large intestine absorb?

Water

What is the order of the 3 parts of the small intestine?

1. Duodenum

2. Jejunu

3. Ileum

What glands of the duodenum secrete dilute/watery alkaline mucus?

Duodenal (Brunner) glands

What is the function of Brunner glands?

Neutralize stomach acid

What part of the small intestine is the widest?

Duodenum

What is the beginning of the superior part of the duodneum?

Duodenal cap (ampulla)

What does the duodenum surround?

Head of pancreas

What is the fibromuscular band that extends from the diaphragm to the duodenojejunal flexure?

Suspensory muscle (ligament) of the duodenum

T/F: The duodenum is entirely retroperitoneal.

False - the duodenal cap is not

Which part of the duodenum is NOT retroperitoneal?

Duodenal cap

What vessels pass anterior to the thrid part of the duodenum?

Superior mesenteric artery and vein

What artery supplies the third and fourth parts of the duodenum?

Inferior pancreaticoduodenal artery

In what part of the duodenum do ulcers occur?

First part (usually in duodenal cap)

Erosion of what artery by a perforated duodenal ulcer can result in severe hemorrhage?

Gastroduodenal artery

What is the name for a perforated duodenal ulcer that presents as appendicitis?

Valentino’s syndrome

What part of the small intestine does the jejunum make up?

proximal two fifths

In what quadrant of the abdomen does the jejunum lie in?

Left upper quadrant

What part of the small intestine does the ileum make up?

distal three fifths

What abdominal quadrant does the ileum occupy?

Right lower quadrant

What segment of the GI tract is the most involved with nutrient uptake?

Jejunum

What does the ileum absorb?

Fat-soluble vitamins, B12, and bile salts

What are the straight terminal branches of the arteries whic htravel throug the mesentery to supply the small intestine?

Vasa recta

What are the circular folds found within the small intestine?

Plicae circulares

What are the aggregations of lymphoid tissue found within the walls of hte small intestine?

Peyer’s patches

What is the function of Peyer’s patches?

Immune defense of the alimentary canal

Compare plicae circulares between the jejunum and ileum.

Jejunum: tall/many

Ileum: short/few

Compare Peyer’s patches between the jejunum and ileum.

Jejunum: absent

Ileum: present

What artery supplies the jejunum and ileum?

Superior mesenteric artery

What provides autonomic innervation to the jejunum and ileum?

Superior mesenteric plexus

What forms Meckel’s diverticulum?

remnant of a portion of the embryonic vitelline duct

What may the symptoms of Meckel’s diverticulum mimic?

Appendicitis

What is the name for an inflammatory bowel disease which most commonly affects the distal ileum and adjacent colon?

Crohn’s disease

What part of the digestive tract does Crohn’s disease usually affect?

Distal ileum and adjacent colon

What are the symptoms of Crohn’s disease?

Pain, diarrhea, malabsorption

What kind of appearance does Crohn’s disease have on X-ray?

Cobblestone

What is most commonly malabsorbed in Crohn’s disease?

Vitamin B12