Digestion & Absorption of Lipids, Absorption of Vitamins & Minerals

Question 1

What are triglycerides?

Answer 1

glycerol and fatty acids

Question 1

Lipids must be solubilized in the _______ for digestion and absorption

Answer 1

small intestine

Question 2

Stomach [quickly/slowly] empties chyme into small intestine

Answer 2

slowly

Question 3

What things help with digestion of lipids?

Answer 3

lipase + colipase
cholesterol ester hydrolase
phospholipase A2

Question 4

What do lipase + collapse do?

Answer 4

collapse binds to lipase and allows it to digest at a lipid-water interface

Question 5

What cholesterol ester hydrolase do?

Answer 5

hydrolyzes cholesterol ester —> free cholesterol + FA + releases glycerol from triglycerides

Question 6

What does phospholipase A2 do?

Answer 6

hydrolyzes phospholipids —> lysolecithin and fatty acids

Question 7

What is phospholipase A2 activated by?

Answer 7

trypsin

Question 8

Bile salts solubilize products within SI lumen as ______ EXCEPT

Answer 8

micelles
glycerol

Question 9

After going into lumen as micelles, they diffuse to the _____ of _______. Products then diffuse into the cell.

Answer 9

brush-border membrane of enterocyte

Question 10

Do bile salts diffuse into the enterocyte?

Answer 10

no

Question 11

After products are released into the cell. products are _____ inside enterocyte to form original compounds

Answer 11

re-esterified

Question 12

Re-esterified lipids are then packaged with _____ to form _______

Answer 12

apoproteins
chylomicrons

Question 13

What do chylomicrons do?

Answer 13

move between endothelial cells of lymphatic capillaries enter blood at thoracic duct

Question 14

In chylomicrons, cholesterol and triglycerides are in the [core/around outside], and apoproteins are in [core/around outside]

Answer 14

core
around outside

Question 15

Chylomicrons are packaged in ________ and exocytosed across basolateral membrane into ________

Answer 15

secretory vesicles
lymphatic capillaries

Question 16

What are some abnormalities of lipid digestion and absorption?

Answer 16

pancreatic insufficiency
acidity of duodenal contents
deficiency of bile salts
bacterial overgrowth
decreased intestinal cells for absorption
failure to synthesize apoproteins

Question 17

What is the pH optimum for lipase?

Answer 17

6

Question 18

A tumor means there is an over-production of ______ - aka too much ________

Answer 18

gastrin
too much HCl (parietal cells)

Question 19

In bacterial overgrowth, bacterial remove ______ & ______ from bile salts

Answer 19

glycine
taurine

Question 20

If there are decreased intestinal cells (enterocytes), there is less ______ for absorption of lipid products

Answer 20

surface area

Question 21

Vitamin absorption is required as ______ or _____ for metabolic reactions

Answer 21

co-enzymes
co-factors

Question 22

Fat-soluble vitamins are incorporated into _____ for transport

Answer 22

chylomicrons

Question 23

Most water-soluble vitamins absorbed via which transport in small intestine? What is the exception?

Answer 23

Na+/dependent co-transport in SI
vitamin B12 (cobalamin), which requires intrinsic factor for absorption

Question 24

Vitamin B12 requires _______ for absorption

Answer 24

intrinsic factor

Question 25

Explain the steps for B12 absorption

Answer 25

Question 26

Need active vitamin D to absorb ______

Answer 26

calcium

Question 27

Calcium is absorbed by both _____ and _____ transport mechanisms

Answer 27

passive
active

Question 28

In active transport, there is [high/low] calcium in the diet. What happens?

Answer 28

high
calbindin synthesis promoted by vitamin D
transport Ca2+ to basolateral membrane

Question 29

In passive transport, there is [high/low] calcium in the diet. Which route?

Answer 29

low
paracellular

Question 30

A lack of vitamin D or calcium causes

Answer 30

rickets (young)
osteomalacia (adult)

Question 31

Iron can occur as ____ iron (Fe2+) OR as _____ iron

Answer 31

free
heme

Question 32

Iron uses which transporter to transport into enterocyte

Answer 32

DMT-1 - LUMINAL membrane

Question 33

The heme iron is digested into _____ by _______ inside enterocytes

Answer 33

free iron
lysosomal enzymes

Question 34

Which transporter does free iron use to cross basolateral membrane into blood?

Answer 34

ferritin (from apoferritin)

Question 35

Iron circulates bound to _____ and is STORED as _______.

Answer 35

transferrin
ferritin