Lipid Absorption/Digestion

Question 1

Most dietary triacylglycerol digestion is completed in

the _______

Answer 1

Lumen of the small intestine

Question 2

Fat digestions starts in the ___ through ___. The serous gland release ___.

Answer 2

Mouth, Mechanical breakdown, Lingual Lipase

Question 3

In the stomach, ____ , produced by ___, provide further digestion of lipids in the stomach, where lingual lipase is also activated here ( 10-30% of lipids digested here by these 2)

Answer 3

Gastric Lipase, Chief cells

Question 4

Gastric lipase readily penetrates milk fat globules without substrate stabilization by bile salts, a feature that makes it particularly important for fat digestion in ____ whose pancreatic function may not be fully developed.

Answer 4

Infants

Question 5

Lingual Lipase + Gastric Lipase prefer to cut ___ and ___ fatty acids at the ___ position (2)

Answer 5

Medium + Short chain fatty acids at the sn-3 position

Question 6

Secretion of both lipase’s ( gastric + lingual) occur continuously but can be stimulated by 3 factors. What are those 3 factors?

Answer 6

1. Amount of fat eaten in diet– more fat, more enzymes
2. Mechanical– sucking( in infants), swallowing
3. Neural factors– thinking of food

Question 7

Breast milk is high in ___ and ___ chain fatty acids, making them easy to absorb for the infant

Answer 7

Short and medium chain

Question 8

Infant formula for pre-term infants is enriched with ___ fatty acids.

Answer 8

Medium-chain

Question 9

Emulsification happens in the stomach through 3 mechanisms. Name these 3 mechanisms.

Answer 9

mixing of bolus by smooth
muscles
shear forces by pyloric sphincter
forming chyme
potential emulsifiers in the acid
milieu of the stomach include
complex polysaccharides,
phospholipids, and peptic digests of
dietary proteins

Question 10

Why do fats make us feel full?

Answer 10

- presence of undigested lipid in
the stomach delays gastric
emptying
- Enterogastrone release may
be responsible for reduced gastric
motility

Question 11

___ is released into the small intestine in the presence of fatty acids and amino acids, and is responsible for stimulating the pancreases and gallbladder to do what? (3)

Answer 11

Cholecystokinin

1. secretion of bile acids
   (complete emulsification of lipid droplets)
2. secretion of pancreatic enzymes
3. secretion of bicarbonate (pancreatic juice)

Question 12

What are some functions of lipids? Name 4 in the body, then 3 Nutrition points + 3 Food industry points

Answer 12

1. Signalling- hormone function, CoQ ( mediator in e- chain), gene expression, pro/anti inflammatory mediators
2. Storage of energy for body
3. Structural functions– Cell membranes ; Brain structure lipids
4. Fat soluble vitamins ie aid in absorbing vitamins A,E,D,K
   Nutrition:
5. Feeling full
6. Provider of energy
7. Provide mouthfeel
   Industry:
8. Taste
9. Emulsifiers
10. Creams, body oils