ch 4 digestion of carbs slide

Question 1

the primary goal of carb digestion is to break down

Answer 1

polysaccharides and disaccharides into monosaccharieds that can then be converted to glucose

Question 2

ograns of the GI tract

Answer 2

• mouth
• stomach
• small intestine
• large intestine

Question 3

organs of the GI tract

mouth

Answer 3

• chewing stimulates secretion of saliva from salivary glands
• salivary amylase breaks down starch into shorter polysaccharides and maltose

ex. amylose—>shorter chains—>maltose
amylopectin—>shorter chains

Question 4

organs of the GI tract

stomach

Answer 4

• salivary amylase is destroyed by acids
• no carb digestion takes place in the stomach

Question 5

organs of the GI tract

small intestine

Answer 5

• pancreatic amylase breaks down remaining starch into maltose
  short chains–>maltose
• specific enzymes (maltase, sucrase, lactase) in small intestine break down disaccharides into monosaccharides
  sucrose–> glucose + fructose
  maltose–> glucose + glucose
  lactose–> glucose + galactose

all monosaccharides are absorbed by the small intestine and enter the bloodstream

Question 6

organs of the GI tract

large intestine

Answer 6

• some carbs pass into the large intestine undigested
• bacteria ferment some undigested carb
• remaining fiber is excreted in feces

Question 7

accessory organs

Answer 7

• salivary glands
• pancreas
• liver

Question 8

accessory organs

salivary glands

Answer 8

produce salivary amylase

Question 9

accessory organs

pancreas

Answer 9

produces digestive enzymes and bicarbonate
which are released into the small intestine via the pancreatic duct

Question 10

accessory organs

liver

Answer 10

• monosaccharides travel to the liver in the bloodstream via the portal vein are converted to glucose and then are transported to body cells to provide energy
• excess glucose is stored in liver and muscles as glycogen