Enzymatic breakdown of which of the following compounds doesn't begin until it reaches the stomach?
answer
protein....enzymatic breakdown of proteins begins in the stomach.
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Which of the following enzymes is important for breaking down protein?
answer
pancreatic lipase.... is important for the digestion of fats. It is secreted by the pancreas and works in the small intestine.
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In the small intestine, which of the following enzymes breaks down maltose?
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maltase...the enzyme maltase breaks down the bonds between the two glucose molecules of the disaccharide maltose.
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The breakdown products of which of the following are absorbed into lacteals?
answer
fats...chylomicrons are absorbed into lacteals because they are too large to pass through the basement membrane of a capillary and into the blood.
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Secretin stimulates the _____ to secrete _____.
answer
pancreas ... bicarbonate....The acidity of the stomach contents triggers the small intestine to secrete secretin, which in turn stimulates the pancreas to secrete bicarbonate to neutralize this acidity.
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Cholecystokinin (CCK) stimulates the _____ to secrete _____.
answer
pancreas ... pancreatic enzymes....The presence of fatty acids and amino acids in the stomach contents triggers the small intestine to secrete CCK. CCK then stimulates the pancreas to secrete enzymes that play a role in the digestion of these nutrients.
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The acidity of the stomach contents triggers the small intestine to secrete a hormone known as _____.
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secretin...The acidity of the stomach contents triggers the small intestine to secrete secretin; secretin then stimulates the pancreas to secrete bicarbonate to neutralize this acidity.
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The presence of fatty acids and amino acids in the stomach contents triggers the small intestine to secrete a hormone known as _____.
answer
cholecystokinin, or CCK...The presence of fatty acids and amino acids in the stomach contents triggers the small intestine to secrete CCK. CCK then stimulates the gall bladder to release bile and the pancreas to secrete pancreatic enzymes.
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Bile is produced by the _____ and stored by the _____ until it is secreted into the small intestine.
answer
liver ... gall bladder....Bile is continuously produced by the liver and is stored in the gall bladder until CCK triggers its release.
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The region of the digestive tract most responsible for absorption of nutrients is __________.
answer
the small intestine
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Which of the GI tract tissue layers is most responsible for peristalsis and segmentation?
answer
muscularis
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Which of the following represents the path taken by food after leaving the mouth?
answer
pharynx, esophagus, stomach, small intestine, large intestine
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The hepatic portal system delivers nutrient-rich blood from the __________ to the __________.
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GI tract; liver....The hepatic portal system connects the GI tract to the liver and delivers nutrient-rich blood to the liver.
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Where does the chemical digestion of proteins begin?
answer
stomach....Protein digestion begins in the acidic environment of the stomach.
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Which of the following statements about the organs of the digestive system is true?
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Although protein digestion begins in the stomach, pancreatic enzymes break the final polypeptide chains into amino acids....Pancreatic enzymes finish up the protein digestive routes by breaking the polypeptide chains into amino acids.
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What would happen if the liver were unable to produce enough bile salts?
answer
Fatty acid absorption would decrease.....Bile salts facilitate the breakdown of complex fats into fatty acids, so decreased production of bile salts would result in decreased fatty acid absorption in the small intestine.
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Which of the following macromolecules go directly from the lumen of the small intestine to the epithelial cells of the intestine and on through to the blood stream?
answer
carbohydrates and proteins... Carbohydrates and proteins, once they have been broken down into their functional units, go directly from the lumen of the intestine, through the epithelial cells, and into the bloodstream.
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Another name for the alimentary canal is ________.
answer
gastrointestinal tract
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Most of the digestion that takes place in the small intestine occurs in the __________.
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duodenum.... is the first section of the small intestine and the site of most digestion.
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When digested, proteins are broken down into _____.
answer
amino acids
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When digested, fats are broken down into _____.
answer
both glycerol and fatty acids
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Starch is a type of _____.
answer
polysaccharide
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Your small intestine can absorb ____ without their being further digested.
answer
fructoses
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Which of these enzymes begins the breakdown of starch?
answer
amylase
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Starch can be broken down into the disaccharide known as _____.
answer
maltose
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Protein digestion begins in the _____.
answer
stomach
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What is the main component of gastric juice?
answer
water
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_____ is secreted by the _____ and acts to emulsify _____ in the _____.
answer
Bile ... liver ... fats ... small intestine...Bile, produced by the liver and stored by the gall bladder, emulsifies fats in the small intestine. The smaller fat droplets present a greater surface area for the action of lipases.
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What acid is responsible for stomach acidity?
answer
hydrochloric acid
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All of the following are secreted into the lumen of the digestive tract during the process of digestion, EXCEPT __________.
answer
hormones
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The gastrointestinal tract is composed of __________.
answer
the hollow organs of the digestive system
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Which layer of the gastrointestinal tract wall is a middle layer of connective tissue containing blood vessels, lymph vessels, and nerves?
answer
submucosa...Food absorbed across the mucosa enters the blood and lymph vessels of the submucosa.
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All of the following are found in saliva, EXCEPT __________.
answer
pepsin
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Mucin, a component of saliva, functions to __________.
answer
hold food particles together
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Malfunction of the lower esophageal sphincter may result in __________.
answer
acid reflux...The lower esophageal sphincter opens to allow food to pass into the stomach and closes to prevent food from flowing back into the esophagus; if it malfunctions, the acid fluids of the stomach may flow back into the esophagus.
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Which of the following might be true of an individual unable to synthesize and secrete intrinsic factor?
answer
He or she would be unable to absorb adequate amounts of vitamin B12.
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Which of the following nutrients are digested within the small intestine?
answer
proteins
carbohydrates
lipids
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Which of the following lists structures in order from smallest to largest?
answer
microvilli, villi, folds, small intestine
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What do the enzymes pepsin, chymotrypsin, trypsin, and carboxypeptidase have in common?
answer
They are enzymes that participate in protein digestion.
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Once nutrients are absorbed into the circulatory system, the next major organ they pass through is the __________.
answer
liver
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Bile is produced by the __________ and stored by the __________.
answer
liver; gallbladder
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Which of the following terms does NOT belong with the others?
answer
peptide
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Each of the following is absorbed into capillaries, EXCEPT __________.
answer
triglycerides
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Which of the following represents the correct sequence in which structures involved in lipid absorption are formed?
answer
micelles, triglycerides, chylomicrons
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Salivation is controlled almost entirely by the nervous system. Which of the following stimuli would inhibit salivation?
answer
fear
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HCl secretions convert pepsinogen to the active hormone pepsin. What cells in the gastric pits produce pepsinogen?
answer
cheif
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In response to a steak dinner, certain secretions are needed to aid digestion. What cells in the pancreas would provide these secretions?
answer
acinar cells
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An increase in HCl (hydrochloric acid) secretion in the duodenum would stimulate which hormone that would help to counteract the effects of HCl?
answer
secretin.... stimulates the duct cells in the pancreas and liver to secrete a bicarbonate-rich solution that will bind hydrogen ions and increase the pH.
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The secretion in the large intestine consists of which of the following?
answer
bicarbonate- and potassium-rich mucus
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Regulation of digestive processes involves primarily the __________.
answer
stomach and small intestine
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How are refined sugar and high fructose corn syrup different?
answer
High fructose corn syrup contains more fructose than refined sugar.
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What, in part, fueled the use of high fructose corn syrup?
answer
High fructose corn syrup is cheaper to produce than refined sugar.
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Which organ converts fructose to fat?
answer
liver
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Approximately how much sugar does the average American consume each year?
answer
90 pounds
question
Which of the following is in the correct order leading to the development of heart disease?
