Digestion and Absorption

Question 1

What secretions does the small intestine receive?

Answer 1

bile, pancreatic juice, chyme

Question 2

What receptors do all secretions of the small intestine act on?

Answer 2

G-protein coupled

Question 3

Which control mechanisms enhance small intestine secretion?

Answer 3

distension, gastrin, CCK, secretin, parasympathetic nerve activity

Question 4

Which control mechanism decreases small intestine secretion?

Answer 4

sympathetic nerve activity

Question 5

Does small intestine secretion contain digestive enzymes?

Answer 5

No

Question 6

What does excessive activity of small intestine secretion cause?

Answer 6

secretory diarrhoea

Question 7

What is segmentation?

Answer 7

mixing

Question 8

Which cells initiate mixing?

Answer 8

pacemaker cells, and in empty ileum, gastrin

Question 9

Which has more mixing, the duodenum or ileum?

Answer 9

duodenum

Question 10

What inhibits peristalsis in the small intestine?

Answer 10

feeding, vagal activity, gastrin, CCK

Question 11

What triggers peristalsis in small intestine?

Answer 11

motilin, lack of feeding

Question 12

Can pancreatic enzymes digest food in absence of all other enzymes?

Answer 12

Yes

Question 13

Which cells secrete HC03 rich fluid into the duodenum?

Answer 13

duct cells

Question 14

What happens to fluid secretion in patients with cystic fibrosis?

Answer 14

is reduced

Question 15

Is bile produced continuously?

Answer 15

Yes

Question 16

What digests carbohydrates in the small intestine?

Answer 16

pancreatic amylase and oligosaccarrides

Question 17

Which glycosidic bonds does amylase break?

Answer 17

alpha 1-4, NOT alpha 1-6 or beta 1-4

Question 18

What causes lactose intolerance?

Answer 18

lactase deficiency

Question 19

What method are glucose and galactose absorbed by?

Answer 19

secondary active transport

Question 20

What method is fructose absorbed by?

Answer 20

Facilitated diffusion

Question 21

What in the stomach cleaves proteins into peptides?

Answer 21

pepsin

Question 22

What type of enzymes are peptidases?

Answer 22

brush border enzymes

Question 23

By what method are most amino acids absorbed?

Answer 23

active transport

Question 24

What increase surface area for attack by pancreatic lipase bu block access of the enzyme to the lipid with the hydrophobic core of the small droplets? What solves this problem?

Answer 24

bile salts

solved by colipase

Question 25

What is colipase?

Answer 25

an ampipathic polypeptide secreted with lipase

Question 26

Where are the final products of lipid digestion stored?

Answer 26

mixed micelles

Question 27

Where are long chain fatty acids and monoglycerides resynthesized to triglycerides?

Answer 27

endoplasmic reticulum

Question 28

By what vein does chylomicron enter the systemic circulation?

Answer 28

subclavian

Question 29

What does absorption of di and tripeptides occur via?

Answer 29

the H+ dependent mechanisms at brush border (co-transport_

Question 30

What is the brush border?

Answer 30

Striated border, microvilli covered surface of epithelium

Question 31

Where do sodium ion independent systems of facilitated transport occur?

Answer 31

basolateral membrane

Question 32

In the stomach, why is lipid hydrolysis initially slow?

Answer 32

due to largely separate aqueous/liquid interface

Question 33

As hydrolysis of fats proceeds, what happens to rate?

Answer 33

increases

Question 34

Are bile salts amphipathic?

Answer 34

Yes

Question 35

What do bile salts have increased surface area for?

Answer 35

action of lipase

Question 36

What does failure to secrete bile salts result in?

Answer 36

Lipid malabsorption and steatorrhea