Digestion and Absorption of Lipids

Question 1

what are molecules of fat?

Answer 1

triglycerides, cholesterol, phospholipids

Question 2

what does aqeous chyme leaving the stomach contain?

Answer 2

coarse emulsion of large fat droplets

Question 3

what does bile salts do in small intestine?

Answer 3

increase surface area for enzymatic fat digestion

Question 4

Bile salts are amphipathic what does this mean?

Answer 4

hydrophic and hydrophilic region

Question 5

what is enzymatic fat digestion carried out by?

Answer 5

lipases - remove 2 fatty acids from each triglyceride molecules

Question 6

How does bile salt coating intestinal emulsion complicate digestion?

Answer 6

lipase cant penetrate bile salts

Question 7

what does fat digestion require?

Answer 7

colipase a protein cofactor secreted by the pancreas it displaces some bile salts allowing lipase access

Question 8

what are phospholipids digested by?

Answer 8

pancreatic phospholipase

Question 9

What fat is not digested but absorbed?

Answer 9

free cholesterol

Question 10

What does digestion of fats coalesce to make?

Answer 10

small micells

Question 11

What do micelles do?

Answer 11

enter unstirred aqueous at edge of brush border

Question 12

how are fatty acids and monoglycerides absorbed?

Answer 12

simple diffusion as move out of micelles and diffuse across enterocyte

Question 13

what does ezetimibe drug do?

Answer 13

inhibit cholesterol absorption by blocked NPC1L1 transporters

Question 14

where do monoglycerides in enterocytes move to?

Answer 14

SER to recombine to triglycerides which join cholesterol to form chylomicrons

Question 15

How are chylomicrons transported?

Answer 15

Packaged into vesicles by golgi and leave cell by exocytosis

Question 16

What are chylomicrons absorbed by?

Answer 16

lacteals the lymph vessels of the villi into the venous blood

Question 17

where does most water absorption take place?

Answer 17

in small intestine and 0.5L in the colon

Question 18

Where does absorption of nutrients do?

Answer 18

moves solute from the lumen of intestine to the ECF creating an osmotic gradient that allows water to flow

Question 19

what do enterocytes and colonocytes absorb?

Answer 19

na using 3 membrane proteins

Question 20

How does K and H2O absorption occur?

Answer 20

in the intestine by paracellular pathway

Question 21

what is route for most drugs?

Answer 21

non-ionised form absorbed by simple passive diffusion

Question 22

What are osmotic factors for fluid accumulation in intestinal lumen?

Answer 22

faulty nutrient digestion and absorption which increase osmotic pressure in lumen

Question 23

What is faulty water absorption due to?

Answer 23

from defective ion transport

Question 24

what is active fluid secretion due to?

Answer 24

capacity of colon to absorb

Question 25

how to treat acute diarrhoea?

Answer 25

oral rehydration therapy 8 tsp of sugar, 1 tsp salt and 1 litre of water