Section 7: Digestion and Absorption of Fats

Question 1

LA funeral director takes in about __ times as much fat as Japaneses coal miner

Answer 1

5

Question 2

True or False? About 75% of consumed fats is absorbed.

Answer 2

F. nearly all

Question 3

What percent of consumed fat is secreted in feces?

Answer 3

0%, excreted fats come from bacteria

Question 4

What produces fat in the feces?

Answer 4

bacteria

Question 5

Steatorrhea is more than __ gm/day of fat in the feces:

Answer 5

6gm/day

Question 6

Organs involve in fat absorption and digestion:

Answer 6

liver, gallbladder, duodenum, ileum, portal blood supply

Question 7

Most dietary fats are :

Answer 7

triglycerides

Question 8

What are the 2 parts to fat digestion?

Answer 8

in lumen, in intestinal epithelial cells

Question 9

In which part of the small intestines does the emulsification of fats take place?

Answer 9

the lumen

Question 10

Bile salts + ? help emulsiy:

Answer 10

lecithin (phospholipid)

Question 11

What aide in the emulsification of fats?

Answer 11

mixing by smooth muscle and HCO3- -rich fluid from pancreas and liver

Question 12

Emulsification work best within this pH range?

Answer 12

6-8.5

Question 13

Function of emulsification:

Answer 13

increases surface area

Question 14

These are both secreted from the pancreas and function in fat digestion:

Answer 14

lipase and colipase

Question 15

Functions of collapse:

Answer 15

aids in lipase attachment, allows lipase to work at lower pH, and prevent inactivation of lipase by bile salts

Question 16

The long chain end of this compound is on the inside of the emulsion droplet:

Answer 16

lecithin

Question 17

Lecithin and phoshoplipids involved in fat breakdown are secreted from:

Answer 17

the liver

Question 18

emulsion droplets are broken down to:

Answer 18

glycerol, monoglycerides, and fatty acids

Question 19

Amphiphilic molecules of fat digestion that can be incorporated into micelles:

Answer 19

detergent molecules, benzene, long-chain alcohol, conjugated trihyroxy bile sale, cholesterol, lecithin

Question 20

True or False? Glycerol is fat soluble.

Answer 20

F. Water soluble

Question 21

Contents of mixed micelles:

Answer 21

2-monoglycerides, free fatty acids and some fat-soluble vitamins

Question 22

What favors the incorporation of fat digestion products into micelles?

Answer 22

high concentrations of amphiphilic compounds in bile

Question 23

The concentration at which micelles form:

Answer 23

critical micelle concentration

Question 24

When and where do mixed micelles form?

Answer 24

at very low concentrations of bile acids, cholesterol and lecithin in the lumen of the small intestine or in the lumen of the gallbladder (especially overnight when bile is concentrated)

Question 25

Can micelles difuse through the unstirred layer?

Answer 25

Yes

Question 26

High concentration of micelles mead rapid diffusion of fats through this layer to the epithelium

Answer 26

unstirred layer, into enterocyte via brush border

Question 27

Compounds that can cross from the lumen into the intracellular space of epithelial cells:

Answer 27

glycerol, monoglyceride, fatty acid, lysolecitihin and cholesterol

Question 28

Compounds that can combine to form chylomicrons in the intracellular space of epithelial cells:

Answer 28

triglycerides, lecithin, cholesterol esters, and free cholesterol

Question 29

How do chylomicrons exit the epithelial cell of the lumen?

Answer 29

exocytosis, then pass through large inter endothelial channels of lymphatic capillaries and enter the lymph

Question 30

fat soluble vitamins are absorbed via this pathway:

Answer 30

micelle-chylomicron pathway

Question 31

True or False? Fat soluble vitamins are digested by lipase.

Answer 31

F

Question 32

What's left of micelles after absorption of fat digestion products, cholesterol and lecithin?

Answer 32

bile acids

Question 33

Can conjugated, unconjugated, or both types of bile acids be absorbed in the ileum?

Answer 33

both, unconjugated: diffusion, conjugated: ASBT (apical sodium bile acid c-transporter)

Question 34

ASBT stands for:

Answer 34

apical sodium bile acid c-transporter

Question 35

Via which type(s) of transport does the absorption of bile acids in the ileum take place?

Answer 35

diffusion and secondary active transport

Question 36

How do bile acids travel from the cells of the ileum to the liver

Answer 36

OSTalpha-OSTbeta (Farnesoid X Receptor?) on the basolateral membrane to the portal blood to the liver

Question 37

What type of circulation is used for bile acids?

Answer 37

enterohepatic circulation

Question 38

Bile acids enter ___ at from the ileum while fat and fat-soluble vitamins enter ___ at the earlier part of the lumen.

Answer 38

portal blood, lymph

Question 39

Most plan and animal fats are thyroid gland made up of __ and ___ fatty acids.

Answer 39

C14 and C18

Question 40

short chain fatty acids are fatty acids of less than __- carbon length.

Answer 40

12

Question 41

Where do we get our supply of short chain fatty acids?

Answer 41

diet or produce by bacteria in the distal intestine.

Question 42

In which part of our body do bacteria produce short chain fatty acids?

Answer 42

distal intestines

Question 43

Are short chain fatty acids absorbed via the micelle-cyloiicron pathway?

Answer 43

no

Question 44

Where are short chain fatty acids absorbed and list 3:

Answer 44

colon: acetate, proppionate, butyrate

Question 45

How do short chain fatty acids get into the cell in the colon?

Answer 45

Either exchanger or diffusion, i.e. SCFA-/HCO3- or butyrate/ Cl-

Question 46

the short chain fatty acids that enter the intracellular space of cells in the colon enter via this type of diffusion:

Answer 46

nonionic

Question 47

True or False? Cholesterol and lecithin are both reabsorbed in the earliest part of the ileum.

Answer 47

F. latest part of the jejunum

Question 48

List 3 ions that are absorbed past immediately past the stomach and before the entry of bile and pancreatic enzymes:

Answer 48

Ca2+, Mg2+, and Fe2+

Question 49

normal dietary fat absorption is ___% efficient.

Answer 49

100%

Question 50

True or False? Absorption of conjugated bile acids in the large intestines is active.

Answer 50

T

Question 51

Immediately past the pancreas fats are hydrolyzed to free fatty acids and ____

Answer 51

2-monoglycerides

Question 52

How many calories does one gram of fat contain?

Answer 52

9 calories

Question 53

How many calories does 1 gram of carbohydrates/ protein have?

Answer 53

4

Question 54

Drug that helps block fat absorption in the body and mechanism of action:

Answer 54

Xenical (orlistat), binds to lipase blocking triglycerides from absorption, creating a calorie deficiency, hydrogenated derivative of lipstatin

Question 55

What is lipstatin a natural product of?

Answer 55

Streptomyces toxyricini

Question 56

Common side effect of alli:

Answer 56

orange fatty discharge (looks like pizza grease), stomach pain, problems controlling bowel movements

Question 57

What can a long term diet too low in fat cause?

Answer 57

depression, skin problems and battle hair and can block absorption of "good" fats like Omega-3's