wk 3 6 Physiology of lipid digestion and absorption of Ca,Fe,vitamins

Question 1

ingested lipids compose of

Answer 1

fats/oils - triaglycerols
phospholipids
cholesterol/cholesterol esters
fatty acids

Question 2

which type of lipids are insoluble/ poorly soluble

Answer 2

insoluble - cholesterol esters

poorly - triaglycerols/cholesterols

Question 3

emulsification

Answer 3

break down of fats

occurs in mouth, stomach, small intestine

Question 4

small lipid droplets are created in emulsification, they will try to recombine t/f

Answer 4

false

negatively charged - repel

Question 5

what is found on the surface of lipids

Answer 5

ampiphatic coat

water phobic/philic areas

Question 6

what is found in lipid coat

Answer 6

multiamellar - fatty acid soap, cholesterol, bile salt

uniamellar - bile salts

Question 7

what mediates lipid digestion in stomach

Answer 7

gastric lipase

gastric phase of digestion only important for pancreatic insufficiency/infants

Question 8

gastrin released causes secretion of

Answer 8

gastric lipase

Question 9

t/f pepsin activates gastric lipase

Answer 9

false

gastric lipase inactivated in duodenum due to pancreatic lipase

Question 10

what does gastric lipase break triglyceride down to

Answer 10

diglyceride + free fatty

Question 11

what does free fatty acids stimulate release

Answer 11

of CCK

Question 12

what is requires to digest lipids in duodenum

Answer 12

pancreatic lipase
bile salts
HCO3-

Question 13

triglyceride - 2-monoacylglyceride + 2 free fatty acids by

Answer 13

pancreatic lipase

Question 14

CCK causes secretion of

Answer 14

bile salts

Question 15

purpose of bile salts

Answer 15

emulsify large lipids

Question 16

what aspect causes lipids once emulsified to stay in small droplets

Answer 16

has a negative charge. so each small lipid will be negatively charged and repel from one another

Question 17

failure of bile salt secretion leads to 2

Answer 17

steatorrhea

ADEK vitamin defiency (since lipid vitamins are not absorbed)

Question 18

t/f lipid digestion only occurs at surface

Answer 18

true

Question 19

bile salts increase surface area for attack by pancreatic lipase. but blocks access of enzyme to hydrophobic core. Which ampipathic polypeptide fies this problem

Answer 19

colipase

starts off as procolipase, trypsin activates

Question 20

which structure stores lipids

Answer 20

mixed
hydrophobic core - containing TAG/esterified cholesterol
monoglycerides,fatty acid, cholesterol, phospholipids are found on surface

Question 21

how are free fatty acids and monoglycerides mostly absorbed

Answer 21

passive diffusion

Question 22

short chain fatty acids/medium onces diffuse through enterocyte, and exit through basolateral membrane and enter villus capillaries. Whatt happens to long chain fattys

Answer 22

(also monoglycerides)

resynthesised to triglycerides in ER and incorporated to Chylomicrons

Question 23

cholesterol is absorbed through

Answer 23

protein binding (NPC1L1) (neimann-pick-C1-like-1)

picks up several cholesterols, catherin coated pit allows endocytosis

Question 24

ezetimibe is used in conjunction with statins in hypercholesterolaemia. what does it do

Answer 24

binds to NPC1L1 - prevents absorption