BIOL 252 | BIOL252 Module 5: Human Anatomy &
Physiology II with Lab Updated and Latest
Questions and Correct Answers with Rationale -
Portage Learning
1. Which of the following enzymes is primarily responsible for the initial chemical digestion of
carbohydrates in the oral cavity?
A. Salivary amylase
B. Pancreatic amylase
C. Lingual lipase
D. Pepsin
Correct Answer: A
Explanation: Salivary amylase is secreted by the salivary glands and begins breaking down
complex starches into maltose. This process represents the first step of chemical digestion
occurring within the mouth. While pancreatic amylase also digests starch, it functions later
in the small intestine. Lingual lipase is present but mostly acts on lipids once they reach the
stomach’s acidic environment. Therefore, salivary amylase is the specific enzyme for initial
oral carbohydrate breakdown.
2. Parietal cells in the gastric mucosa are responsible for secreting which of the following
substances?
A. Pepsinogen
B. Gastrin
C. Hydrochloric acid (HCl)
D. Mucus
Correct Answer: C
Explanation: Parietal cells are specialized cells located in the gastric pits of the stomach
lining. Their primary role is the secretion of hydrochloric acid which lowers the gastric pH
to facilitate protein denaturation. Additionally, these cells produce intrinsic factor, which is
necessary for the absorption of vitamin B12. Chief cells are responsible for pepsinogen,
whereas G cells produce the hormone gastrin. This secretion of HCl is vital for activating
enzymes and killing ingested pathogens.
3. Which hormone is released in response to the presence of fat and protein in the
duodenum, causing the gallbladder to contract?
A. Secretin
,B. Cholecystokinin (CCK)
C. Insulin
D. Motilin
Correct Answer: B
Explanation: Cholecystokinin or CCK is a peptide hormone produced by the mucosal cells
of the duodenum. It is triggered by the entry of chyme containing fats and proteins from
the stomach. CCK stimulates the gallbladder to contract and release stored bile into the
cystic duct. It also signals the pancreas to release digestive enzymes into the small
intestine. This regulation ensures that bile is available for the emulsification of dietary
lipids.
4. Most of the nutrient absorption in the human digestive system occurs in which specific
segment?
A. Stomach
B. Large intestine
C. Esophagus
D. Jejunum
Correct Answer: D
Explanation: The small intestine is divided into the duodenum, jejunum, and ileum
segments. The jejunum is characterized by a high surface area due to numerous villi and
microvilli. This structural adaptation makes it the primary site for the absorption of sugars,
amino acids, and fatty acids. While the duodenum starts the process, the bulk of chemical
absorption is completed in the jejunum. The large intestine primarily focuses on water and
electrolyte reabsorption rather than nutrient uptake.
5. What is the primary function of bile salts during the digestion process?
A. Chemical breakdown of proteins
B. Neutralization of stomach acid
C. Emulsification of lipids
D. Absorption of water
Correct Answer: C
Explanation: Bile salts are detergent-like molecules produced by the liver and stored in
the gallbladder. Their main function is to break large fat globules into smaller droplets
through a process called emulsification. This increase in surface area allows pancreatic
lipases to work more efficiently on the lipids. Without bile salts, fat digestion and
, subsequent absorption would be significantly impaired. Thus, they play a mechanical
rather than a purely chemical role in lipid processing.
6. Which structure prevents the reflux of gastric contents back into the esophagus?
A. Lower esophageal (cardiac) sphincter
B. Ileocecal valve
C. Pyloric sphincter
D. Upper esophageal sphincter
Correct Answer: A
Explanation: The lower esophageal sphincter is a ring of muscle located at the junction of
the esophagus and stomach. It remains closed under normal conditions to prevent acidic
chyme from moving upward. Failure of this sphincter to close properly can lead to
gastroesophageal reflux disease or GERD. The pyloric sphincter, by contrast, regulates the
movement of chyme into the duodenum. Therefore, the cardiac sphincter is essential for
protecting the esophageal lining from acid damage.
7. Which of the following is an inactive protease secreted by the pancreas that is activated by
enterokinase?
A. Trypsinogen
B. Chymotrypsin
C. Carboxypeptidase
D. Pepsinogen
Correct Answer: A
Explanation: The pancreas secretes several zymogens to prevent self-digestion of the
pancreatic tissue. Trypsinogen is one such inactive enzyme that is released into the
duodenum. Upon reaching the intestinal brush border, it is converted to active trypsin by
the enzyme enterokinase. Active trypsin then goes on to activate other pancreatic
proteases like chymotrypsinogen. This cascading mechanism ensures that protein
digestion occurs only within the intestinal lumen.
8. Intrinsic factor is required for the absorption of which essential nutrient?
A. Calcium
B. Vitamin B12
C. Iron
D. Vitamin C
Correct Answer: B
Physiology II with Lab Updated and Latest
Questions and Correct Answers with Rationale -
Portage Learning
1. Which of the following enzymes is primarily responsible for the initial chemical digestion of
carbohydrates in the oral cavity?
A. Salivary amylase
B. Pancreatic amylase
C. Lingual lipase
D. Pepsin
Correct Answer: A
Explanation: Salivary amylase is secreted by the salivary glands and begins breaking down
complex starches into maltose. This process represents the first step of chemical digestion
occurring within the mouth. While pancreatic amylase also digests starch, it functions later
in the small intestine. Lingual lipase is present but mostly acts on lipids once they reach the
stomach’s acidic environment. Therefore, salivary amylase is the specific enzyme for initial
oral carbohydrate breakdown.
2. Parietal cells in the gastric mucosa are responsible for secreting which of the following
substances?
A. Pepsinogen
B. Gastrin
C. Hydrochloric acid (HCl)
D. Mucus
Correct Answer: C
Explanation: Parietal cells are specialized cells located in the gastric pits of the stomach
lining. Their primary role is the secretion of hydrochloric acid which lowers the gastric pH
to facilitate protein denaturation. Additionally, these cells produce intrinsic factor, which is
necessary for the absorption of vitamin B12. Chief cells are responsible for pepsinogen,
whereas G cells produce the hormone gastrin. This secretion of HCl is vital for activating
enzymes and killing ingested pathogens.
3. Which hormone is released in response to the presence of fat and protein in the
duodenum, causing the gallbladder to contract?
A. Secretin
,B. Cholecystokinin (CCK)
C. Insulin
D. Motilin
Correct Answer: B
Explanation: Cholecystokinin or CCK is a peptide hormone produced by the mucosal cells
of the duodenum. It is triggered by the entry of chyme containing fats and proteins from
the stomach. CCK stimulates the gallbladder to contract and release stored bile into the
cystic duct. It also signals the pancreas to release digestive enzymes into the small
intestine. This regulation ensures that bile is available for the emulsification of dietary
lipids.
4. Most of the nutrient absorption in the human digestive system occurs in which specific
segment?
A. Stomach
B. Large intestine
C. Esophagus
D. Jejunum
Correct Answer: D
Explanation: The small intestine is divided into the duodenum, jejunum, and ileum
segments. The jejunum is characterized by a high surface area due to numerous villi and
microvilli. This structural adaptation makes it the primary site for the absorption of sugars,
amino acids, and fatty acids. While the duodenum starts the process, the bulk of chemical
absorption is completed in the jejunum. The large intestine primarily focuses on water and
electrolyte reabsorption rather than nutrient uptake.
5. What is the primary function of bile salts during the digestion process?
A. Chemical breakdown of proteins
B. Neutralization of stomach acid
C. Emulsification of lipids
D. Absorption of water
Correct Answer: C
Explanation: Bile salts are detergent-like molecules produced by the liver and stored in
the gallbladder. Their main function is to break large fat globules into smaller droplets
through a process called emulsification. This increase in surface area allows pancreatic
lipases to work more efficiently on the lipids. Without bile salts, fat digestion and
, subsequent absorption would be significantly impaired. Thus, they play a mechanical
rather than a purely chemical role in lipid processing.
6. Which structure prevents the reflux of gastric contents back into the esophagus?
A. Lower esophageal (cardiac) sphincter
B. Ileocecal valve
C. Pyloric sphincter
D. Upper esophageal sphincter
Correct Answer: A
Explanation: The lower esophageal sphincter is a ring of muscle located at the junction of
the esophagus and stomach. It remains closed under normal conditions to prevent acidic
chyme from moving upward. Failure of this sphincter to close properly can lead to
gastroesophageal reflux disease or GERD. The pyloric sphincter, by contrast, regulates the
movement of chyme into the duodenum. Therefore, the cardiac sphincter is essential for
protecting the esophageal lining from acid damage.
7. Which of the following is an inactive protease secreted by the pancreas that is activated by
enterokinase?
A. Trypsinogen
B. Chymotrypsin
C. Carboxypeptidase
D. Pepsinogen
Correct Answer: A
Explanation: The pancreas secretes several zymogens to prevent self-digestion of the
pancreatic tissue. Trypsinogen is one such inactive enzyme that is released into the
duodenum. Upon reaching the intestinal brush border, it is converted to active trypsin by
the enzyme enterokinase. Active trypsin then goes on to activate other pancreatic
proteases like chymotrypsinogen. This cascading mechanism ensures that protein
digestion occurs only within the intestinal lumen.
8. Intrinsic factor is required for the absorption of which essential nutrient?
A. Calcium
B. Vitamin B12
C. Iron
D. Vitamin C
Correct Answer: B
