6.2 Digestion and Absorption

Question 1

HCL function in the stomach

Answer 1

Gastric pits release HCL
1. provides an acidic medium that cancels the effect of saliva, thus maintaining a pH value below 7
2. kills bacteria present in food
3. HCL converts the inactive enzyme of pepsinogen into the active form of pepsin (breaks down proteins and turns them into amino acids).
4. denature proteins

Question 2

Know that protein digestion begins in stomach

Answer 2

mechanical digestion (physically breakdown food), Food entering stomach causes distention (stretch receptors release enzymes causing chem digestion), produce chyme (semi fluid mass of partially digested food)

Question 3

most chemical digestion begins in small intestine

Answer 3

hydrolysis (enzymes)-macromolecules hydrolyzed into smaller molecules. Gives different chemical composition through enzyme-catalyzed reactions

Question 4

hormonal and nervous mechanisms that control secretion, content and volume of gastric juices

Answer 4

xx

Question 5

role of pancreas in digestion

Answer 5

the pancreas produces a variety of enzymes that breakdown major good groups and secreted thru duct into lumen of SI
secretin stimulates pancreas

Question 6

Enzymes

Answer 6

Amylase, Lipase, Trypsin, and Nuclease all produced in increased and activated in lumen of SI. all slightly alkaline

Question 7

diff methods of membrane transport required to absorb different nutrients

Answer 7

1. Diffusion - fatty acids and other non polar substances easily pass through hydrophobic cell membranes of epithelial cells through simple diffusion
2. Osmosis - water diffuses across epithelial cells membranes in response to the movement of ions and other hydrophilic monomers
3. Active transport - glucose and aa pumped againsts conc. gradient or transported with NA ions bc actively pumped against conc gradient

Question 8

role of large intestine

Answer 8

main function-absorption of water
–secretes mucus
–movement of undigested / food products
–egestion (materials not absorbed) BELCH
–cellulose and lignin (not digested bc humans do not posses enzymes or gut bacteria to break them down break down alpha not beta

Question 9

role of fiber in diet

Answer 9

more fiber=faster role of transit=less exposure to undesirable food=chemicals decrease contact time btwn intestinal wall and food

Question 10

fiber does…

Answer 10

-clean out old damaged intestinal cells and unabsorbed materials
-provide bulk to keep materials moving
-absorb water to keep feces soft
-decrease hunger
-“works out” bodies bacteria
-reduce constipation
-lowers risk of colon cancer
-lower blood cholesterol

Question 11

ULCERS (Helicobacter Pylori)

Answer 11

ulcers-inflamed damaged areas of open sores in stomach

Question 12

causes and consequences of PKU

Answer 12

genetically inhereted disease caused by the inability to metabolize amino acid phenylene to tyrosine
phenalylinye builds up in tissue and blood due to lack of enzyme that breaks down phenylene from inheriting mutated form of a gene
treatment– lowp rotein in diet to limit intake of protein sources that contatin phenylene and supplement with formual containing essential AAs