Chapter 17

Question 1

1. What are the three source in which fat comes from?
2. What releases fatty acids?
3. What happens in the duodenum?
   
   1. What does this process depend on?

Answer 1

1. Consumed in diet, fat stored in adipose tissue, fat synthesized in one organ (carbohydrates to fat in liver) and for export to other organ that mainly live of fat (liver, heart and resting skeletal muscle).
2. Fatty acid release by lipases in low pH environment of stomach.
3. Secretion of alkaline pancreatic juice - this raises the pH and allows pancreatic lipases and non-specific esterases to hydrolyze the ester linkages and set the fatty acid chains free from glycerol
   
   1. Bile Acids: Amphipathic compounds that work as detergents and form micelles with the triaglycerides and increase accessibility for water soluble lipase and esterase.

Question 2

1. What are chylomicrons?
2. What protrude from the surface in these structures?
3. How are fatty acids processed?

Answer 2

1. Spherical aggregates with phospholipids outside and triglycerides (~80%) sequestered inside.
2. Several apo-lipoproteins protrude from surface.
3. Transported through lymphatic system and bloodstream → In capillaries of these tissues: Extracellular lipoprotein lipases (activated by lipoprotein) hydrolyze triglycerides in fatty acids and glycerol → Uptake of fatty acids and glycerol in tissues.