Lecture 9.A. - Lipid Absorption

Question 1

Pancreatic Lipase is secreted in _____ (active or inactive?) form. It requires _______, which is secreted in _____ (active or inactive?) form to bind emulsion lipid droplets and displace ____ _____.

Lipase + ______ digestion products = 2 ____ ___ ____ and 1 _________.

Answer 1

Active

Colipase

Inactive

Bile Salts

Colipase

2 FFAs

1 Monoglyceride

Question 2

____ _____ and ______ A-2 are both nonspecific Pancreatic lipases.

Answer 2

Cholesterol Esterase

Phospholipase A-2

Question 3

There is _____ (fast or slow?) digestion of large lipid droplets before they are emulsified by bile salts. When bile salts bind and emulsify lipid droplets, there is NO digestion bc they displace lipases. Which Pancreatic enzyme facilitates the displacement of bile salts and re-binding of Lipases?

Answer 3

Slow

Colipase

Question 4

Diffusion through the _____ layer of contents in the intestinal lumen is the rate limiting step for fat absorption. Without _____ transporting fatty acids to the apical surface of the brush boarder, fat absorption would be far less efficient.

Answer 4

Unstirred Layer

Micelles

Question 5

Though fatty acids diffuse across cell membranes readily, they are also transported via intestinal transporters. What is the relationship between length of the fatty acid chain and likelihood of requiring a transporter?

Once the fatty acids are in the cytosol, they bind ______ to prevent efflux.

Answer 5

The longer the chain, the more likely it needs a transporter.

FABP (Fatty Acid Binding Protein)

Question 6

Free cholesterol from the diet can be absorbed via NPC1L1. _______ is a medication that blocks this transporter.

Bc cholesterol is a larger molecule, its transport is more efficient than its _____.

Answer 6

Ezetimibe

Diffusion

Question 7

FAs are processed in the _____ and then wrapped in the _____ with Apolipoproteins, making them _______.

Answer 7

SER

RER

Chylomicrons

Question 8

Chylomicrons are too large to pass through the basolateral membran of intestinal cells, so they are exocytosed into ______, enter circulation via the _____ duct, and are brought to the _____ for processing.

Answer 8

Lymph

Thoracic duct

Liver

Question 9

________ is a disease in which intestinal cells cannot produce ______, so they become engorged with fat.

Answer 9

Abetalipoproteinemia

Chylomicrons

Question 10

______ ______ is the enzyme that breaks down chylomicrons, releasing FAs for use in skeletal + cardiac muscle or storage in adipose tissue.

Answer 10

Lipoprotein Lipase

Question 11

How do you distinguish between bile and pancreatic insufficiency and Celiac disease?

Answer 11

Both present with malabsorption of lipids, but Celiac will also show Villus atrophy.