Section 4A

Question 1

The duodenum ends at a sharp bend called what?

Answer 1

Duodenojejunal flexure (junction)

Question 2

What 4 things are occurring in the duodenum?

Answer 2

1. Stomach acid is neutralized here
2. Fats are broken up by bile acids
3. Pepsin is inactivated by the elevated pH
4. Pancreatic enzymes take over the job chemical digestion

Question 3

How long is the jejunum?

Answer 3

About 8 feet long

Question 4

How long is the ileum?

Answer 4

About 12 feet long

Question 5

At what structural point does the ileum join the large intestine?

Answer 5

The ileocecal valve

Question 6

How does the small intestine maximize its surface area?

Answer 6

Through plicae circulares, villi and microvilli

Question 7

Which cells produce mucous in the intestinal villi?

Answer 7

Goblet cells

Question 8

What 3 things do enteroendocrine cells of the intestinal villi secrete?

Answer 8

CCK, Secretin, GIP

Question 9

What cells of the intestinal vill divide to replace themselves and the other types of epithelial cells?

Answer 9

Regenerative cell

Question 10

What does the paneth cells do of the intestinal villi?

Answer 10

Secrete the antibacterial enzyme lysozyme and other antibacterial agents

Question 11

What cells possess a layer of closely packed microvilli, enzymes (brush border) and transporters

Answer 11

Surface absorptive cells

Question 12

Sucrose, Lactose and Maltose are made up of what simple sugars respectively?

Answer 12

Sucrose: Glucose and Fructose
Lactose: Glucose and Galactose
Maltose: Glucose and Glucose

Question 13

3 most common examples of Polysaccharides?

Answer 13

Glycogen
Starch
Cellulose

Question 14

What does pancreatic amylase do?

Answer 14

Degrades polysaccharides into disaccharides and “oligosaccharides”

Question 15

What enzymes degrade disaccharides in the small intestine?

Answer 15

Brush border enzymes called disaccharidases

Question 16

What does the Na+-dependent co-transporter SGLT1 do?

Answer 16

It absorbs Gucose and Galactose via secondary active transport

Question 17

How is Fructose absorbed into the small intestinal cells?

Answer 17

Via GLUT5 by facilitated diffusion

Question 18

Does the absorption of fructose require Na+

Answer 18

No

Question 19

How are monosaccharides transported out of the enterocytes and into capillaries?

Answer 19

By GLUT2 via facilitated diffusion

Question 20

Where does amino acid degradation mainly occur?

Answer 20

Although the stomach does a good job of denaturing proteins, it does not do a good job of denaturing proteins. This occurs mainly at the brush border with aminopeptidases and active pancreatic enzymes

Question 21

What enzymes at the brush border are the main culprit to cleaving off amino acids

Answer 21

Aminopeptidases

Question 22

How are MOST amino acids absorbed in small intestine?

Answer 22

By the same co transport mechanism utilized by glucose. However, some amino acids do not require this sodium co-transport but instead are transported like fructose by facilitated diffusion