Digestion and Absorption QUIZ

Question 1

Roles of Hydrochloric Acid in the Stomach

Answer 1

Created when stretch receptors send impulses to medulla oblongata to create HCl
Denatures proteins
Kills harmful pathogens
HCl Conditions in the stomach favor hydrolysis reactions
HCl production is inhibited by PPIs

Question 2

General function of villi and be able to explain how the structure of a villus is related to its function

Answer 2

Increases surface area
ABSORPTION
Absorbs nutrients, vitamins, minerals
Lacteals, veins, arteries

Question 3

Different forms of transport used by the small intestine to absorb different nutrients (and know which nutrients are absorbed using each form of transport)

Answer 3

1. Diffusion:
   Fatty acids and other small,
   non-polar substances
   easily pass through the
   hydrophobic cell
   membranes of
   epithelial cells through simple diffusion
2. Osmosis: Water diffuses across epithelial cell membranes in response to movement of
   ions and other hydrophilic monomers (occurs in small intestine and large intestine)
3. Facilitated Diffusion:
   Protein channels within epithelial cell membranes (of villi and microvilli) allow passage of hydrophilic food molecules (water-soluble/ polar molecules like fructose, vitamins, glucose, amino acids, and minerals)
4. Active Transport - requires ATP:
   Glucose and amino acids are pumped (membrane proteins) against their concentration gradients, or they are transported with Na+ ions (co-transport) as Na+ ions are actively pumped across the membrane (secondary active transport)
5. Endocytosis:
   Invagination of the cell membrane to form a vesicle around bulk fluids/ large molecules that must remain intact in the intestinal lumen and bring them into the cell (pinocytosis: “cell drinking”)
   Example: Absorption of antibodies (such as those in breastmilk – passed on to infants)

Question 4

What does BELCH stand for and what does it mean?

Answer 4

Bile Pigments
Epithelial Cells of Intestine
Lignin
Cellulose
Human microflora (bacteria)
All things that are egested

Question 5

Which bacteria causes stomach ulcers?

Answer 5

Helicobacter pylori