4A A&P and Pathology of Small Intestine

Question 1

How long is the duodenum?

Answer 1

First 10-12 inches of the small intestine

Question 2

Where does the duodenum end?

Answer 2

Duodenojejunal flexure

Question 3

How long is the jejunum? Ileum?

Answer 3

8 feet long.

12 feet long

Question 4

What is the longest section of the small in intestine? Shortest?

Answer 4

Ileum is the longest. Duodenum is the shortest

Question 5

How is maximal surface area achieved in the small intestine?

Answer 5

Via plicae circulares, villi, and microvilli

Question 6

What are plicae circulares?

Answer 6

Finger-like extensions in the lumen of the small intestine - Macrovilli

Question 7

What is the difference between villi and microvilli?

Answer 7

Villi project off of the plicae circulares. Microvilli project off of individual cells (enterocytes) that make up the villi

Question 8

Are villi present in the large and small intestine?

Answer 8

Only in the small intestine

Question 9

What kind (shape) of cells are enterocytes?

Answer 9

Tall columnar cells

Question 10

Are crypts present in the large and small intestine?

Answer 10

Yes, the both have crypts

Question 11

What is in the core of each villus?

Answer 11

Blood (vein and artery) capillaries and lymphatic capillaries

Question 12

What is the crypt of Liberkuhn?

Answer 12

The crypts of the small and large intestine that are lined with a variety of enterocytes

Question 13

What kind of cells line the crypts and villi of the small intestine?

Answer 13

Surface absorptive cells, goblet cells, enteroendocrine cells, regenerative cells, and paneth cells

Question 14

What do goblet cells produce?

Answer 14

Mucus

Question 15

What do enteroendocrine cells produce?

Answer 15

CCK, secretin and GIP

Question 16

Where are regenerative cells found in the small intestine?

Answer 16

Bottom of the crypts

Question 17

What are Paneth cells?

Answer 17

Secrete the antibacterial enzyme lysozyme and other antibacterial agents

Question 18

What are three common monosaccharides?

Answer 18

Glucose, Fructose, Galactose

Question 19

What are three common disaccharides?

Answer 19

Sucrose (glucose and fructose), lactose (galactose and glucose), maltose (glucose and glucose)

Question 20

What are three common polysaccharides?

Answer 20

Glycogen, starch, cellulose

Question 21

Are there any enzymes in the stomach that breakdown carbs?

Answer 21

No

Question 22

What does pancreatic amylase breakdown?

Answer 22

Polysaccharides into disaccharides and oligosaccharides

Question 23

What are disaccharides degraded by?

Answer 23

A group of brush border enzymes called disaccharidases

Question 24

How do glucose and galactose get absorbed in the small intestine?

Answer 24

Via SGLT1 (secondary active transport)

Question 25

Can glucose and galactose be absorbed in the small intestine w/o a sodium gradient?

Answer 25

No, glucose and galactose rely on the sodium gradient to go into the enterocytes against their own gradient

Question 26

What is the only way that the small intestine can absorbed glucose into the body?

Answer 26

Via the SGLT1 cotransporter

Question 27

What does GLUT5 facilitate?

Answer 27

Absorption of fructose by facilitated diffusion

Question 28

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

Answer 28

Via GLUT2 (facilitated diffusion)

Question 29

How does hyponatremia affect carb absorption?

Answer 29

When sodium concentration is low, glucose is not able to be absorbed via the SGLT1

Question 30

What monosaccharides can move thru GLUT2?

Answer 30

Glucose, galactose, and fructose

Question 31

Why does lactose intolerance occur?

Answer 31

Lack of the lactase enzyme

Question 32

Where does the cleaving off of amino acids occur mainly?

Answer 32

At the brush border w/ aminopeptidases and with the active pancreatic enzymes (proteases)

Question 33

T/F most amino acids or small peptides are transported into enterocytes via the same co-transport mechanism as utilized by glucose?

Answer 33

T but some do not require the sodium co-transport mechanism by instead are taken in the same way as fructose - via facilitated diffusion