Lecture 9 Flashcards
Effects of SCFAs on the GI Tract:
Stimulates H2O and Na+ absorption into the mucosal cells of the colon
Promote differentiation and proliferation of mucosal cells of the colon
Enhance immune function and prevent the growth of potentially harmful cells
Decreases pH that reduce bile solubility (less available to interact with cells) and increase Ca2+ binding to bile and fatty acids; causes things to move out of the large intestine; may provide protection against colon cancer
Provide energy for colonic cells
Inhibit hepatic cholesterol synthesis
Enhance colonic blood flow
What is the effect of SCFAs on water and sodium absorption in the GI tract?
SCFAs stimulate water and sodium absorption into the mucosal cells of the colon.
How do SCFAs affect the mucosal cells of the colon?
SCFAs promote differentiation and proliferation of mucosal cells of the colon.
What role do SCFAs play in the immune function of the GI tract?
SCFAs enhance immune function and prevent the growth of potentially harmful cells.
How do SCFAs influence pH levels in the colon and what is the impact on bile and fatty acids?
SCFAs decrease pH, which reduces bile solubility (making less bile available to interact with cells) and increases calcium binding to bile and fatty acids. This process may provide protection against colon cancer.
What is the role of SCFAs in providing energy within the GI tract?
SCFAs provide energy for colonic cells.
How do SCFAs affect cholesterol synthesis?
SCFAs inhibit hepatic cholesterol synthesis.
What effect do SCFAs have on colonic blood flow?
SCFAs enhance colonic blood flow.
Effects of Fibre on Nutrient Digestion and Absorption
Delays stomach emptying and alters small intestine transit time
Decreases the mixing of GI contents with digestive enzymes
Reduces digestive enzyme function
Reduces nutrient diffusion
Reduces glycemic response to food
Decreased absorption of lipids
Increased bile acid excretion
Decreased cholesterolemia
How does fiber affect stomach emptying and small intestine transit time?
Fiber delays stomach emptying and alters small intestine transit time by forming a viscous gel-like mass which slows down the rate of stomach emptying.
What is the impact of fiber on the transit time in the small intestine?
Fiber accelerates transit time in the small intestine and triggers contractions.
How does fiber affect the mixing of gastrointestinal contents with digestive enzymes?
Fiber decreases the mixing of GI contents with digestive enzymes, reducing digestive enzyme function as it obstructs enzyme access to other components like carbohydrates, fats, and proteins.
What effect does fiber have on nutrient diffusion within the digestive system?
Fiber reduces nutrient diffusion and blocks nutrients from reaching the enterocytes from the lumen.
How does fiber influence the glycemic response to food?
Fiber reduces the glycemic response by slowing down the digestion and absorption of carbohydrates.
What are the effects of fiber on lipid absorption and cholesterol levels?
Fiber decreases the absorption of lipids, increases bile acid excretion, and decreases cholesterolemia. The liver compensates by using cholesterol to produce more bile.
