Digestive Physiology
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AP Biology › Digestive Physiology
One of the functions of the liver is .
to produce bile, triglycerides, and cholesterol
to act as the main storage center for bile
to secrete epinephrine and norepinephrine
to physically digest food
to produce insulin in its specialized beta cells
Explanation
The liver has a large number of functions, including metabolizing toxins, synthesizing proteins, and storing glucose in the form of glycogen. The only answer choice that describes liver functions is the production of bile, triglycerides, and cholesterol.
The pancreas produces insulin from beta cells, the gall bladder stores bile, and the adrenal medulla secretes epinephrine and norepinephrine. Physical digestion takes place mainly in the mouth and stomach, not the liver.
One of the functions of the liver is .
to produce bile, triglycerides, and cholesterol
to act as the main storage center for bile
to secrete epinephrine and norepinephrine
to physically digest food
to produce insulin in its specialized beta cells
Explanation
The liver has a large number of functions, including metabolizing toxins, synthesizing proteins, and storing glucose in the form of glycogen. The only answer choice that describes liver functions is the production of bile, triglycerides, and cholesterol.
The pancreas produces insulin from beta cells, the gall bladder stores bile, and the adrenal medulla secretes epinephrine and norepinephrine. Physical digestion takes place mainly in the mouth and stomach, not the liver.
Bile salts make fat droplets more accessible to the enzyme .
pancreatic lipase
trypsin
chymotrypsin
pepsin
lingual lipase
Explanation
Once large fat clusters are broken down by bile salts to become smaller micelles, pancreatic lipase has more surface area to access fats. The enzymes are able to reach the fat droplet through the gaps between bile salts. Fats are not emulsified by bile yet in the mouth, so lingual lipase acts upstream of bile to hydrolize long chain hydrocarbons. The other answer choices are proteases.
Bile salts make fat droplets more accessible to the enzyme .
pancreatic lipase
trypsin
chymotrypsin
pepsin
lingual lipase
Explanation
Once large fat clusters are broken down by bile salts to become smaller micelles, pancreatic lipase has more surface area to access fats. The enzymes are able to reach the fat droplet through the gaps between bile salts. Fats are not emulsified by bile yet in the mouth, so lingual lipase acts upstream of bile to hydrolize long chain hydrocarbons. The other answer choices are proteases.
Which digestive system organ secretes enzymes vital for lipid digestive, and where are these enzymes introduced into the digestive tract?
Enzymes from the pancreas are introduced into the duodenum
Enzymes from the liver are introduced into the stomach
Enzymes from the liver are introduced into the colon
Enzymes from the pancreas are introduced into the stomach
Explanation
Lipase is synthesized and secreted from the pancreas into the duodenum of the small intestine. Lipase plays a key role in the digestion of lipids.
What is the major enzyme in saliva that acts on carbohydrates?
Salivary amylase
Lingual lipase
Salivary trypsin
Lingual pepsin
Lingual amylase
Explanation
Salivary amylase in the mouth targets large starch molecules and begins the digestion process to a monosaccharide (i.e. glucose). Salivary amylase secretion is stimulated by the recognition of starch on sweet taste receptors, and is carried out by the salivary glands (parotid, submandibular, and sublingual).
Which digestive system organ secretes enzymes vital for lipid digestive, and where are these enzymes introduced into the digestive tract?
Enzymes from the pancreas are introduced into the duodenum
Enzymes from the liver are introduced into the stomach
Enzymes from the liver are introduced into the colon
Enzymes from the pancreas are introduced into the stomach
Explanation
Lipase is synthesized and secreted from the pancreas into the duodenum of the small intestine. Lipase plays a key role in the digestion of lipids.
Amylase is a digestive enzyme responsible for breaking down which macromolecules found in food?
Carbohydrates
Proteins
Lipids
Nucleic acids
None of these
Explanation
The correct answer is carbohydrates because amylase is the enzyme that is able to break these macromolecules down into smaller parts. There are two kinds of amylase found in the body, salivary amylase in the mouth and pancreatic amylase in the pancreas. Both of these are involved in the breakdown of carbohydrates in digestion.
Which of the following statements about the hormone secretin is false?
All of these choices are correct
It is released when acid enters the duodenum, where it is secreted
It stimulates bicarbonate secretion in the pancreas
It inhibits motility in the stomach
Explanation
Secretin is a hormone released by the duodenum in response to an influx of acid. The hormone targets the stomach, to reduce the amount of acid that can pass through to the small intestine, and the pancreas, to increase secretion of bicarbonate, which neutralizes the acidity.
Bile salts are amphipathic and essential for fat absorption. Which of the following nutrients will be difficult to absorb in a patient with an inability to secrete bile salts into the stomach?
I. Vitamin A
II. Vitamin B
III. Vitamin C
I only
II only
I and II
I and III
All of these
Explanation
Bile salt emulsifies fat into chylomicrons to allow for absorption. Of the choices, only vitamin A is fat-soluble. Vitamins B and C are both water-soluble.