Digestion and Absorption of Fats in the Monogastric Alimentary Tract and their fate in the body + Bile pigments

Question 1

what componets make up Triglycerides?

Answer 1

Triglycerides are made up of 1 glycerol molecule and 2 fatty acids( aycyl chains)

Question 2

what are monoglycerides?

Answer 2

Monoglycerides are simpler forms of truglycerides. They have one or more acyl chains esterified to glycerol

Question 3

What is the difference between unsaturated and staurated fats?

Answer 3

unsaturated fats are have more then one double bond. this results in their being a kink in the chain which reduces the melting point of the trglyceride molecule.
saturated fats have no double bonds

Question 4

what other types of lipids are taken in by the small intestine?

Answer 4

• phosplipids from cell membranes
• cholesterol froom animal cell fat stores
• cholesterol from animal cell membranes

Question 5

what is the emultification of fats and what substance is reponsible for it?

Answer 5

The break down of big molecules of fat into smaller molecules and its done by bile salts and amphipathic lipids.

Question 6

why is it difficult to digest, absorb and tranport TAG?

Answer 6

It is difficult to digest, absorb and tranport fats in the small intestine because fats are insoluble in water.

Question 7

How is the problem of lipid trasnport overcome?

Answer 7

the lipid absorded is coated in a rich protein and amiphatic lipids

Question 8

what two places does emulsification of lipids occur?

Answer 8

emulification of lipids occurs first in the mouth then in the stomach at 37 degrees,

Question 9

what is the purpose of lipid emulification?

Answer 9

emulification increases the surface area for lipid droplets for digestive enzymes.

Question 10

what is the function of bile salts an amphipathic lipids?

Answer 10

bile salts and amphipathic lipids coat small emulified particles and prevent them from re-aggrecating into bulk TAG

Question 11

what enzyme breaks down lipids?

Answer 11

lipase is reponsible for the breakdown TAG.

Question 12

what is the function of enterocyte cells that line the jejunum?

Answer 12

enterocyte cells are highly absopative cells.

Question 13

what is used to produce bile salts in the liver?

Answer 13

Bile salts are produced by cholestrol in the liver.

Question 14

what happens in the duodenum during fat breakdown?

Answer 14

pancreatic lipase and bile salts are secreted in this region and assist in the emulification of the fat.

Question 15

what happens at the jejunum during fat breakdown?

Answer 15

The jejunum is a highly absopative region which is composed of enterocyte cells. Its the region where fat is absorbed and the production of chylomicrons occurs.

Question 16

what happens at the illeum doing fat breakdown?

Answer 16

bile salts reabsorbed and are returned to the liver and a small perecntage leaves with feaces.

Question 17

what are phospholipids broken down into and what enzyme is responsible for this?

Answer 17

phospolipids are broken down into free fatty acids and lipolipids.
phospholipase A is reponsible

Question 18

what does cholestrol break down into and what enzyme is reposible?

Answer 18

cholestrol breaks down into free fatty acids and free cholestrol.
cholestrolesterhypolase (wrong spelling) is responsible

Question 19

what does TAG (tryglycerides) break down into and what enzyme is responsible?

Answer 19

TAG breaks down into free fatty acids and glycerol

lipase is reponsible and co-lipase

Question 20

explain the steps of fat break down ( so start with a fat molecule)

Answer 20

A fat molecule enters the duodenum. Pancreatic lipase first bind to the fat molecule and breaks it down into smaller droplets.
Bile salts then bind to these fat droplets and stop the binding of lipase to allow for stabilisation.
Bile salts and Co-lipase then both bind to the droplet and stop lipase from binding.

Question 21

which places produce lipid breaking down enzymes and what are the names of the enzymes.

Answer 21

The Ebners glad produces lingual lipase.
The stomach the secretion of gastric lipase.
Pancreas= pancreatic trigylceride lipase, phospholipases and cholesteral esterases .

Question 22

how much does the average person intake of fat in western country?
what is the recomended dietary intake?

Answer 22

100- 150 grams of fat daily and this is 40 percent but the recomended intake is 25 percent.

Question 23

what are examples opf fat soluble vitamins?

Answer 23

A D E K

Question 24

Explain the steps of lipid absoption?

Answer 24

lipids are digested by lipase, bile salts and co-lipase (other enyzyemes for other fats). The product of this digestion is miscels. These then migrate to the enterocyte walls of the jejunum where their excrete lipid products into the cell.
Once in the cell the free fatty acids and phospholipids, cholestrol esterase, TAGS are then reseterised.
the resterised lipids and lipoproteins combine with apo(lipo) proteins to form CHYLOMICRONS.
CHYLOMICRONS then migrate to the basolateral membrane where they are excreted via exytosis into the blood.

Question 25

where is bile produced and stored?

Answer 25

bile is produced by colestrol in the hepatocyte cells in the liver and is then stored in the gall bladder.

Question 26

what are primary bile acids?

Answer 26

cholic and chenodeoxycholic acids

Question 27

where are secondary bile acids produced?

Answer 27

secondary bile acids are produced by bacterial action in the small intestine.

Question 28

How is bile released into the duodenum?

Answer 28

when food is in the stomach the duodenal mucosa produces CCK, which enters the intestine. this causes the gall bladder to contract and the oddi splincter to relax which allows the entry of bile.

Question 29

whats the importance of the oddi splincter?

Answer 29

The oddi splicter remains contacted and shut to prevent the entery of bile into the small intestine when they are not required.

Question 30

whos more at risk of gall stones?

Answer 30

caucasion, females, low fibres , high cholestrol, starchy diet and overweight.

Question 31

why is the digestion of fat usually incomplete?

Answer 31

TAG are first broken down into diglycerides and this process in fast ( gastric lipase/ pancreatic lipase) Diglycerides are often broken down into monoglycerides and this process is also fast. monoglycerides are then broken down into gylcerol and a fatty acid by this process is very slow so digestion is usually incomplete.

Question 32

what are micelles?

Answer 32

micelles are solutions of lipids that consist of lipid digestion products

Question 33

the importance of the unstired layer of water between two vili of the small intestine?

Answer 33

enures the micelles are concentrated and taken up by carreir medicated regions

Question 34

where does the re-esterification of TAGS occur in the cell and what happens?

Answer 34

phospholipid and protein are added to TAG droplet passes from the endoplasmic reticulum to the golgi aparatus where glycoation of proteins occues. vitamins, cholestrol and fat soluble vitamins are added to chylomicrons.

Question 35

where do the chylomicrons enter circulation?

Answer 35

chylomicrons enter circulation via the thoracic lymph ducts because they are too big to cross cappilaries.

Question 36

what enzyme facilitates the entry of chylomicrons.

Answer 36

lipoprotein lipase