Question 1

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-secreted by the salivary glands
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Amylase is the enzyme secreted by the salivary glands that initiates the breakdown of carbohydrates in the mouth.

Question 2

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-fat digestion begins
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Accepted Answer

Fat digestion commences and is completed in the lumen of the small intestine with the help of bile salts and pancreatic lipase.

Answer: A and B
 Digestion of carbohydrates and proteins commences in the mouth and stomach, respectively, through the action of salivary amylase and pepsin. However, digestion of carbohydrates is not completed in the mouth, and digestion of proteins is not completed in the stomach.

Answer: D
 Intracellular digestion of carbohydrates and proteins occurs in the small intestine brush border with the help of enzymes such as maltase, sucrase, lactase, and peptidases.

Answer: E
 The colon is not involved in the digestion of any of the three main categories of foodstuffs. It mainly absorbs water and electrolytes from the remaining undigested material before excretion as feces.

Question 3

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-activated by HCl
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Pepsin(ogen) is activated by HCl in the stomach to break down proteins into smaller peptides.

Answer: A
 Bile salts aid in the digestion and absorption of fats by emulsifying them into smaller droplets.

Answer: E
 Trypsin(ogen) is activated in the small intestine by the pancreatic enzyme enterokinase and breaks down proteins into smaller peptides.

Answer: D
 Lipase is secreted by the pancreas and breaks down fats into fatty acids and glycerol.

Answer: C
 Amylase is secreted by the salivary glands and pancreas and breaks down carbohydrates (starch) into smaller sugars.

Question 4

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-exerts detergent action
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Bile salts are responsible for exerting detergent action, helping to emulsify fats and make them more accessible to lipase for breakdown.

Answer: B
 Pepsin(ogen) is responsible for the initial breakdown of proteins in the stomach.

Answer: C
 Amylase is responsible for the breakdown of carbohydrates into simple sugars in the mouth and small intestine.

Answer: D
 Lipase is responsible for breaking down fats into fatty acids and glycerol in the small intestine.

Answer: E
 Trypsin(ogen) is responsible for breaking down proteins in the small intestine.

Question 5

Match the stimuli, labelled a. through d., with the descriptions. (Options may be used more than once or not at all.)
-stimulates secretion of secretin
A)fat in the duodenum
B)acid in the duodenum
C)acid in the stomach
D)protein in the stomach

Accepted Answer

Secretin is secreted by the S cells of the duodenum in response to acidic contents (low pH) entering the duodenum from the stomach. Its main role is to neutralize the acidic chyme through the secretion of bicarbonate from the pancreas.

Question 6

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-enzyme that digests fat
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Lipase is the enzyme that digests fat.

Answer: A
 Bile salts aid in the digestion and absorption of fats by emulsifying them into smaller droplets.

Answer: E
 Trypsin(ogen) is an enzyme that breaks down proteins in the small intestine. It is secreted by the pancreas.

Options B and C are not matching any descriptions provided.

Question 7

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-potent choleretic
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Bile salts are the only secretion among the options listed that is a potent choleretic, meaning it stimulates the production and release of bile from the liver and gallbladder.

Answer: B and E
 Pepsin and trypsin are both digestive enzymes that break down proteins, and their precursors are listed as options (pepsinogen and trypsinogen). However, both enzymes are produced in different parts of the digestive system (pepsin in the stomach, trypsin in the pancreas) and have different activation mechanisms.

Question 8

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-carbohydrate digestion is completed
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Accepted Answer

Carbohydrate digestion is completed intracellularly in the small intestine brush border where enzymes like maltase, sucrase, and lactase break down disaccharides into monosaccharides.

Question 9

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-fat digestion is completed
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Accepted Answer

Fat digestion commences in the small intestine lumen with the action of bile and pancreatic lipase. It is completed in the same location with the further action of lipase on the emulsified fat droplets.

Question 10

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-activated by enterokinase
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Enterokinase is an enzyme secreted by the small intestine that activates trypsinogen into trypsin, making option E the correct match.

Answer: A 
 Bile salts are secreted by the liver and stored in the gallbladder, and are not enzymes that are activated by enterokinase. It is used to emulsify fats in the small intestine, so they can be digested by lipase. Therefore, option A is not the correct match.

Answer: B 
 Pepsinogen is an inactive precursor of pepsin, which is activated by the acidic environment in the stomach. Therefore, option B is not the correct match.

Answer: C 
 Amylase is an enzyme that breaks down carbohydrates and is secreted by both the pancreas and salivary glands. It requires no activation by enterokinase, making option C not the correct match.

Answer: D 
 Lipase is an enzyme that breaks down fats and is secreted by the pancreas. It requires no activation by enterokinase, making option D not the correct match.

Question 11

Match the stimuli, labelled a. through d., with the descriptions. (Options may be used more than once or not at all.)
-most potent stimulus for inhibition of gastric motility
A)fat in the duodenum
B)acid in the duodenum
C)acid in the stomach
D)protein in the stomach

Accepted Answer

Fat in the duodenum is the most potent stimulus for inhibition of gastric motility.

Question 12

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-protein digestion begins
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Accepted Answer

Protein digestion begins in the stomach with the action of the enzyme pepsin and is completed in the small intestine lumen with the help of proteases secreted by the pancreas.

Answer: A, C, and D
 Carbohydrate digestion begins in the mouth with the action of amylase, continues in the small intestine lumen with the help of pancreatic amylase, and is completed intracellularly within the small intestine brush border with the action of various disaccharidases.

Answer: B and C
 Fat digestion begins in the stomach with the action of lipase and is completed in the small intestine lumen with the help of bile salts, pancreatic lipase, and various other lipases secreted by the pancreas.

Question 13

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-carbohydrate digestion begins
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Accepted Answer

Carbohydrate digestion begins in the mouth with the action of salivary amylase.

Answer: C and D
 Carbohydrate digestion is completed in the lumen of the small intestine with the help of pancreatic amylase and brush border enzymes.

Answer: B and E
 Stomach and colon do not play significant roles in carbohydrate digestion.

Question 14

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.)
-protein digestion is completed
A)mouth
B)stomach
C)small intestine lumen
D)intracellularly in the small intestine brush border
E)colon

Accepted Answer

Protein digestion is completed intracellularly in the small intestine brush border.

Question 15

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-pancreatic enzyme that digests protein
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Trypsin(ogen) is a pancreatic enzyme specifically involved in the digestion of proteins, fitting the description provided.

Question 16

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-gastric enzyme that digests protein
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Pepsin(ogen) is the gastric enzyme that specifically digests protein in the stomach.

Answer: D
 Lipase is a digestive enzyme secreted by the pancreas that breaks down fats into fatty acids and glycerol in the small intestine.

Other options:
A) Bile salts are produced by the liver and stored in the gallbladder. They aid in the digestion and absorption of fat molecules in the small intestine.
C) Amylase is a digestive enzyme secreted by the pancreas and salivary glands that breaks down carbohydrates into simple sugars in the small intestine.
E) Trypsin(ogen) is a pancreatic enzyme that digests protein in the small intestine.

Question 17

Match the stimuli, labelled a. through d., with the descriptions. (Options may be used more than once or not at all.)
-stimulates secretion of CCK
A)fat in the duodenum
B)acid in the duodenum
C)acid in the stomach
D)protein in the stomach

Accepted Answer

The release of CCK in response to the presence of fat in the duodenum is a well-known physiological response.

Answer: B
 Acid in the duodenum can trigger the release of hormones such as secretin, but not necessarily CCK.

Answer: C
 Acid in the stomach would not trigger the release of CCK, as it is a hormone that is primarily involved in the regulation of digestive enzymes and bile release from the pancreas and gallbladder in response to the presence of fat and protein in the small intestine.

Answer: D
 Protein in the stomach would not trigger the release of CCK, as it is a hormone that is primarily involved in the regulation of digestive enzymes and bile release from the pancreas and gallbladder in response to the presence of fat and protein in the small intestine.

Question 18

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-recycled many times through the enterohepatic circulation
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Bile salts are recycled many times through the enterohepatic circulation.

Answer: B
 Pepsin(ogen) is not involved in the enterohepatic circulation, amylase and lipase do not recycle through the circulation, and trypsin(ogen) does not participate in digestion until it is activated in the small intestine.

Therefore, only choice A (bile salts) and only choice B (pepsin(ogen)) fit their respective descriptions.

Question 19

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-forms micelles to aid fat absorption
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Bile salts are responsible for emulsifying fats, forming micelles to aid in the absorption of fat in the small intestine.

Answer: D
 Lipase is the enzyme responsible for the breakdown and digestion of fats in the small intestine. It breaks down triglycerides into glycerol and fatty acids, which can then be absorbed by the body.

Question 20

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.)
-pancreatic enzyme that digests carbohydrate
A)bile salts
B)pepsin(ogen)
C)amylase
D)lipase
E)trypsin(ogen)

Accepted Answer

Amylase is the pancreatic enzyme that digests carbohydrates.

Answer: A 
 Bile salts aid in the emulsification and absorption of lipids.

Answer: D 
 Lipase is the pancreatic enzyme that digests lipids.

Answer: E 
 Trypsin(ogen) is a pancreatic enzyme that aids in the digestion of proteins.

Answer: B 
 Pepsin(ogen) is not a pancreatic enzyme, but rather an enzyme produced by the stomach that aids in the digestion of proteins.

Quiz 15: The Digestive System

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -secreted by the salivary glands

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.) -fat digestion begins

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -activated by HCl

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -exerts detergent action

Match the stimuli, labelled a. through d., with the descriptions. (Options may be used more than once or not at all.) -stimulates secretion of secretin

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -enzyme that digests fat

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -potent choleretic

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.) -carbohydrate digestion is completed

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.) -fat digestion is completed

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -activated by enterokinase

Match the stimuli, labelled a. through d., with the descriptions. (Options may be used more than once or not at all.) -most potent stimulus for inhibition of gastric motility

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.) -protein digestion begins

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.) -carbohydrate digestion begins

Indicate the site, labelled a. through e., at which digestion of each of the three main categories of foodstuffs commences and is completed. (Options may be used more than once or not at all.) -protein digestion is completed

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -pancreatic enzyme that digests protein

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -gastric enzyme that digests protein

Match the stimuli, labelled a. through d., with the descriptions. (Options may be used more than once or not at all.) -stimulates secretion of CCK

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -recycled many times through the enterohepatic circulation

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -forms micelles to aid fat absorption

Match the digestive secretions, labelled a. through e., to the descriptions. (Options may be used more than once or not at all.) -pancreatic enzyme that digests carbohydrate