, 26/27 BIOL 121/BIOD 121 MODULE 2 EXAM |
NUTRITION -PORTAGE | Q&A + DETAILED
RATIONALES
1. During digestion, a bite of food follows the normal gastrointestinal pathway. Which
sequence correctly traces its movement from ingestion toward elimination?
A) Mouth → pharynx → esophagus → stomach → small intestine → large intestine →
rectum → anus
B) Mouth → stomach → pharynx → small intestine → esophagus → colon → anus
C) Mouth → esophagus → liver → stomach → small intestine → rectum → colon
D) Mouth → pharynx → pancreas → stomach → colon → small intestine → anus
Correct Answer: Mouth → pharynx → esophagus → stomach → small intestine → large
intestine → rectum → anus
Rationale: The alimentary canal is a continuous muscular tube extending from the mouth
to the anus. Food is ingested in the mouth, passes through the pharynx and esophagus,
enters the stomach, proceeds through the small intestine and then the large intestine, and
ultimately reaches the rectum and anus. The liver and pancreas contribute digestive
secretions but food does not normally pass through them.
2. A digestive organ produces bile but does not store it. Which organ performs this
function?
A) Pancreas
B) Gallbladder
C) Liver
D) Stomach
Correct Answer: Liver
Rationale: Hepatocytes in the liver produce bile. Bile travels through the biliary system and
may be stored and concentrated in the gallbladder between meals. When dietary fat enters
the small intestine, bile can be released into the duodenum, where bile salts facilitate lipid
digestion by emulsifying large fat droplets.
3. Food never passes through several organs that nevertheless make essential
contributions to digestion. Which set consists entirely of accessory digestive organs?
A) Stomach, liver, and pancreas
B) Liver, gallbladder, and pancreas
C) Esophagus, pancreas, and colon
D) Stomach, small intestine, and gallbladder
Correct Answer: Liver, gallbladder, and pancreas
,Rationale: The liver, gallbladder, and pancreas are accessory digestive organs because they
contribute secretions or other functions to digestion without being part of the lumen
through which food travels. The liver produces bile, the gallbladder stores and
concentrates bile, and the pancreas supplies digestive enzymes and bicarbonate to the small
intestine.
4. Chewing a piece of bread into progressively smaller fragments illustrates which process
most directly?
A) Absorption
B) Chemical digestion
C) Mechanical digestion
D) Elimination
Correct Answer: Mechanical digestion
Rationale: Mechanical digestion physically breaks food into smaller pieces without
changing the fundamental chemical identity of its nutrients. Chewing increases surface
area, allowing digestive enzymes greater access to food molecules. Chemical digestion
differs because it uses enzymes and other digestive agents to break chemical bonds in
macromolecules.
5. After swallowing, a food bolus continues moving toward the stomach even without
assistance from gravity. What mechanism primarily accounts for this movement?
A) Segmentation
B) Emulsification
C) Diffusion
D) Peristalsis
Correct Answer: Peristalsis
Rationale: Peristalsis consists of coordinated waves of contraction and relaxation in
gastrointestinal smooth muscle that propel luminal contents forward. This mechanism
allows the esophagus to transport a swallowed bolus toward the stomach even when gravity
is not providing meaningful assistance. Segmentation primarily mixes rather than propels
intestinal contents over long distances.
6. A meal enters the stomach and is repeatedly mixed with acidic gastric secretions. The
resulting semiliquid material is called:
A) Bolus
B) Bile
C) Chyme
D) Chylomicron
Correct Answer: Chyme
, Rationale: Chyme is the acidic, semifluid mixture produced when gastric contractions
combine swallowed food with gastric juice. A bolus is the mass formed in the mouth for
swallowing. Bile is a digestive secretion involved in fat processing, whereas a chylomicron is
a lipoprotein particle involved in transporting absorbed dietary lipids.
7. Localized contractions move intestinal contents backward and forward, repeatedly
mixing them with digestive secretions without primarily transporting them long
distances. This movement is:
A) Peristalsis
B) Segmentation
C) Mastication
D) Deglutition
Correct Answer: Segmentation
Rationale: Segmentation consists of localized contractions, particularly in the small
intestine, that mix chyme with digestive juices and repeatedly expose nutrients to the
absorptive intestinal surface. Peristalsis has a stronger propulsive function. Mastication
means chewing, and deglutition refers to swallowing.
8. Damage to intestinal villi would most directly compromise which gastrointestinal
function?
A) Nutrient absorption
B) Bile synthesis
C) Saliva production
D) Gastric acid secretion
Correct Answer: Nutrient absorption
Rationale: Villi and microvilli greatly increase the absorptive surface area of the small
intestine. Damage or flattening of these structures reduces the area available for nutrients
to cross the intestinal epithelium, potentially producing malabsorption even when digestion
itself is partially intact.
9. The duodenum receives acidic chyme from the stomach. Which pancreatic secretion is
especially important for creating a more favorable environment for intestinal digestive
enzymes?
A) Hydrochloric acid
B) Bicarbonate
C) Bile salts
D) Intrinsic factor
Correct Answer: Bicarbonate
Rationale: Pancreatic bicarbonate helps neutralize acidic chyme entering the duodenum.
This protects the intestinal mucosa and raises luminal pH toward the range in which many
NUTRITION -PORTAGE | Q&A + DETAILED
RATIONALES
1. During digestion, a bite of food follows the normal gastrointestinal pathway. Which
sequence correctly traces its movement from ingestion toward elimination?
A) Mouth → pharynx → esophagus → stomach → small intestine → large intestine →
rectum → anus
B) Mouth → stomach → pharynx → small intestine → esophagus → colon → anus
C) Mouth → esophagus → liver → stomach → small intestine → rectum → colon
D) Mouth → pharynx → pancreas → stomach → colon → small intestine → anus
Correct Answer: Mouth → pharynx → esophagus → stomach → small intestine → large
intestine → rectum → anus
Rationale: The alimentary canal is a continuous muscular tube extending from the mouth
to the anus. Food is ingested in the mouth, passes through the pharynx and esophagus,
enters the stomach, proceeds through the small intestine and then the large intestine, and
ultimately reaches the rectum and anus. The liver and pancreas contribute digestive
secretions but food does not normally pass through them.
2. A digestive organ produces bile but does not store it. Which organ performs this
function?
A) Pancreas
B) Gallbladder
C) Liver
D) Stomach
Correct Answer: Liver
Rationale: Hepatocytes in the liver produce bile. Bile travels through the biliary system and
may be stored and concentrated in the gallbladder between meals. When dietary fat enters
the small intestine, bile can be released into the duodenum, where bile salts facilitate lipid
digestion by emulsifying large fat droplets.
3. Food never passes through several organs that nevertheless make essential
contributions to digestion. Which set consists entirely of accessory digestive organs?
A) Stomach, liver, and pancreas
B) Liver, gallbladder, and pancreas
C) Esophagus, pancreas, and colon
D) Stomach, small intestine, and gallbladder
Correct Answer: Liver, gallbladder, and pancreas
,Rationale: The liver, gallbladder, and pancreas are accessory digestive organs because they
contribute secretions or other functions to digestion without being part of the lumen
through which food travels. The liver produces bile, the gallbladder stores and
concentrates bile, and the pancreas supplies digestive enzymes and bicarbonate to the small
intestine.
4. Chewing a piece of bread into progressively smaller fragments illustrates which process
most directly?
A) Absorption
B) Chemical digestion
C) Mechanical digestion
D) Elimination
Correct Answer: Mechanical digestion
Rationale: Mechanical digestion physically breaks food into smaller pieces without
changing the fundamental chemical identity of its nutrients. Chewing increases surface
area, allowing digestive enzymes greater access to food molecules. Chemical digestion
differs because it uses enzymes and other digestive agents to break chemical bonds in
macromolecules.
5. After swallowing, a food bolus continues moving toward the stomach even without
assistance from gravity. What mechanism primarily accounts for this movement?
A) Segmentation
B) Emulsification
C) Diffusion
D) Peristalsis
Correct Answer: Peristalsis
Rationale: Peristalsis consists of coordinated waves of contraction and relaxation in
gastrointestinal smooth muscle that propel luminal contents forward. This mechanism
allows the esophagus to transport a swallowed bolus toward the stomach even when gravity
is not providing meaningful assistance. Segmentation primarily mixes rather than propels
intestinal contents over long distances.
6. A meal enters the stomach and is repeatedly mixed with acidic gastric secretions. The
resulting semiliquid material is called:
A) Bolus
B) Bile
C) Chyme
D) Chylomicron
Correct Answer: Chyme
, Rationale: Chyme is the acidic, semifluid mixture produced when gastric contractions
combine swallowed food with gastric juice. A bolus is the mass formed in the mouth for
swallowing. Bile is a digestive secretion involved in fat processing, whereas a chylomicron is
a lipoprotein particle involved in transporting absorbed dietary lipids.
7. Localized contractions move intestinal contents backward and forward, repeatedly
mixing them with digestive secretions without primarily transporting them long
distances. This movement is:
A) Peristalsis
B) Segmentation
C) Mastication
D) Deglutition
Correct Answer: Segmentation
Rationale: Segmentation consists of localized contractions, particularly in the small
intestine, that mix chyme with digestive juices and repeatedly expose nutrients to the
absorptive intestinal surface. Peristalsis has a stronger propulsive function. Mastication
means chewing, and deglutition refers to swallowing.
8. Damage to intestinal villi would most directly compromise which gastrointestinal
function?
A) Nutrient absorption
B) Bile synthesis
C) Saliva production
D) Gastric acid secretion
Correct Answer: Nutrient absorption
Rationale: Villi and microvilli greatly increase the absorptive surface area of the small
intestine. Damage or flattening of these structures reduces the area available for nutrients
to cross the intestinal epithelium, potentially producing malabsorption even when digestion
itself is partially intact.
9. The duodenum receives acidic chyme from the stomach. Which pancreatic secretion is
especially important for creating a more favorable environment for intestinal digestive
enzymes?
A) Hydrochloric acid
B) Bicarbonate
C) Bile salts
D) Intrinsic factor
Correct Answer: Bicarbonate
Rationale: Pancreatic bicarbonate helps neutralize acidic chyme entering the duodenum.
This protects the intestinal mucosa and raises luminal pH toward the range in which many
