Exam 4: Lecture 59: Digestion and Absorption of lipids, absorption, vitamins, and minerals Flashcards
What are the three main types of dietary lipids?
Triglycerides, cholesterol, and phospholipids
Why is churning important for initiation of lipid digestion?
It breaks the lipids into small droplets to increase surface area
What is the first step of the SI digestion of lipids?
Bile salts emulsify lipids
What substance must be present with lipase in order for it to digest at lipid-water interface?
Colipase
Which enzyme releases glycerol from triglycerides?
Cholesterol ester hydrolase
Which enzyme is activated by trypsin?
Phospholipase A2
How do Bile salts solubilize products in the SI lumen?
Using micelles
T/F: Micelles and bile salts both diffuse into the enterocyte.
False - bile salts DO NOT diffuse into the enterocyte
Chylomicrons are comprised of what?
Re-esterified lipids packaged with apoproteins
Chylomicrons are packaged in vesicles and exocytosed to where?
Lymphatic capillaries
Why are chylomicrons exocytosed into the lymphatic system and directly into the circulatory system?
They are too big for the vascular capillaries, they will enter the blood at the thoracic duct
A problem at any step of digestion or absorption of lipids can cause what?
Steatorrhea
What are six common abnormalities of lipid digestion/absorption?
- Pancreatic insufficiency
- Acidity of duodenal contents
- Deficiency of bile salts
- Bacterial overgrowth
- Decreased intestinal cells for absorption
- Failure to synthesize apoproteins
What enzyme is essential for proper function of pancreatic lipase?
A. Phospholipase A2
B. Cholesterol ester hydrolase
C. Gastric lipase
D. Colipase
D
Why would a bacterial overgrowth cause abnormalities in lipid digestion/absorption?
The bacteria removes glycine and taurine from bile salts, they will then be bile acids again and readily absorbed by diffusion into enterocytes.
