,BIOD151/BIOD 151 Module 3 Exam | Essential Human
Anatomy & Physiology I with Lab | Portage Learning | Q & A |
2026/2027 Edition (PDF)
1. Which of the following best describes the primary role of the digestive system?
A) To transport oxygen to tissues
B) To break down food into absorbable nutrients
C) To filter waste from the blood
D) To regulate body temperature
Correct Answer: To break down food into absorbable nutrients
Rationale: The digestive system's main function is to break down food mechanically and chemically into
smaller molecules that can be absorbed into the bloodstream. Oxygen transport is the role of the
respiratory and cardiovascular systems, while waste filtration is primarily renal.
2. What is the correct sequence of the five stages of digestion?
A) Ingestion, Digestion, Absorption, Compaction, Defecation
B) Digestion, Ingestion, Absorption, Compaction, Defecation
C) Ingestion, Absorption, Digestion, Compaction, Defecation
D) Compaction, Ingestion, Digestion, Absorption, Defecation
Correct Answer: Ingestion, Digestion, Absorption, Compaction, Defecation
Rationale: The five stages of digestion occur in a specific order: ingestion (taking in food), digestion
(breaking it down), absorption (nutrients entering the blood), compaction (forming feces), and
defecation (eliminating waste). This sequence reflects the progressive processing of food through the
alimentary canal.
3. According to the structural organization of the digestive system, which of the following is an accessory
organ?
,A) Stomach
B) Small intestine
C) Liver
D) Pharynx
Correct Answer: Liver
Rationale: The liver is an accessory organ of the digestive system, meaning it aids in digestion but food
does not pass through it. The stomach, small intestine, and pharynx are all part of the alimentary canal
(GI tract).
4. What is the primary function of the hormone ghrelin?
A) To decrease hunger and increase satiety
B) To increase hunger and decrease satiety
C) To stimulate the release of bile
D) To inhibit gastric acid secretion
Correct Answer: To increase hunger and decrease satiety
Rationale: Ghrelin is known as the "hunger hormone." It is produced in the stomach and signals the
brain to increase appetite and promote food intake. Leptin, in contrast, decreases hunger and increases
satiety.
5. Which layer of the alimentary canal is responsible for secreting mucus to protect the underlying
tissues?
A) Serosa
B) Muscularis externa
C) Submucosa
D) Mucosa
, Correct Answer: Mucosa
Rationale: The mucosa is the innermost layer of the alimentary canal and is responsible for secretion of
mucus, enzymes, and hormones, as well as absorption. The serosa is the outermost protective layer, the
muscularis externa provides motility, and the submucosa contains blood vessels and nerves.
6. What is the primary function of the pyloric sphincter?
A) To prevent backflow of food from the stomach into the esophagus
B) To regulate the passage of chyme from the stomach into the small intestine
C) To control the entry of bile into the duodenum
D) To separate the ileum from the cecum
Correct Answer: To regulate the passage of chyme from the stomach into the small intestine
Rationale: The pyloric sphincter is a muscular valve located at the base of the stomach. It relaxes to
allow small amounts of chyme to pass from the stomach into the duodenum (first part of the small
intestine) and contracts to prevent backflow.
7. Which of the following is NOT a function of the large intestine?
A) Absorption of water
B) Absorption of electrolytes
C) Absorption of vitamins produced by bacteria
D) Absorption of nutrients from digested food
Correct Answer: Absorption of nutrients from digested food
Rationale: The large intestine primarily absorbs water, electrolytes, and certain vitamins (like vitamin K)
produced by gut bacteria. The absorption of most nutrients (carbohydrates, proteins, fats) occurs in the
small intestine.
8. What is the primary function of the hormone leptin?
Anatomy & Physiology I with Lab | Portage Learning | Q & A |
2026/2027 Edition (PDF)
1. Which of the following best describes the primary role of the digestive system?
A) To transport oxygen to tissues
B) To break down food into absorbable nutrients
C) To filter waste from the blood
D) To regulate body temperature
Correct Answer: To break down food into absorbable nutrients
Rationale: The digestive system's main function is to break down food mechanically and chemically into
smaller molecules that can be absorbed into the bloodstream. Oxygen transport is the role of the
respiratory and cardiovascular systems, while waste filtration is primarily renal.
2. What is the correct sequence of the five stages of digestion?
A) Ingestion, Digestion, Absorption, Compaction, Defecation
B) Digestion, Ingestion, Absorption, Compaction, Defecation
C) Ingestion, Absorption, Digestion, Compaction, Defecation
D) Compaction, Ingestion, Digestion, Absorption, Defecation
Correct Answer: Ingestion, Digestion, Absorption, Compaction, Defecation
Rationale: The five stages of digestion occur in a specific order: ingestion (taking in food), digestion
(breaking it down), absorption (nutrients entering the blood), compaction (forming feces), and
defecation (eliminating waste). This sequence reflects the progressive processing of food through the
alimentary canal.
3. According to the structural organization of the digestive system, which of the following is an accessory
organ?
,A) Stomach
B) Small intestine
C) Liver
D) Pharynx
Correct Answer: Liver
Rationale: The liver is an accessory organ of the digestive system, meaning it aids in digestion but food
does not pass through it. The stomach, small intestine, and pharynx are all part of the alimentary canal
(GI tract).
4. What is the primary function of the hormone ghrelin?
A) To decrease hunger and increase satiety
B) To increase hunger and decrease satiety
C) To stimulate the release of bile
D) To inhibit gastric acid secretion
Correct Answer: To increase hunger and decrease satiety
Rationale: Ghrelin is known as the "hunger hormone." It is produced in the stomach and signals the
brain to increase appetite and promote food intake. Leptin, in contrast, decreases hunger and increases
satiety.
5. Which layer of the alimentary canal is responsible for secreting mucus to protect the underlying
tissues?
A) Serosa
B) Muscularis externa
C) Submucosa
D) Mucosa
, Correct Answer: Mucosa
Rationale: The mucosa is the innermost layer of the alimentary canal and is responsible for secretion of
mucus, enzymes, and hormones, as well as absorption. The serosa is the outermost protective layer, the
muscularis externa provides motility, and the submucosa contains blood vessels and nerves.
6. What is the primary function of the pyloric sphincter?
A) To prevent backflow of food from the stomach into the esophagus
B) To regulate the passage of chyme from the stomach into the small intestine
C) To control the entry of bile into the duodenum
D) To separate the ileum from the cecum
Correct Answer: To regulate the passage of chyme from the stomach into the small intestine
Rationale: The pyloric sphincter is a muscular valve located at the base of the stomach. It relaxes to
allow small amounts of chyme to pass from the stomach into the duodenum (first part of the small
intestine) and contracts to prevent backflow.
7. Which of the following is NOT a function of the large intestine?
A) Absorption of water
B) Absorption of electrolytes
C) Absorption of vitamins produced by bacteria
D) Absorption of nutrients from digested food
Correct Answer: Absorption of nutrients from digested food
Rationale: The large intestine primarily absorbs water, electrolytes, and certain vitamins (like vitamin K)
produced by gut bacteria. The absorption of most nutrients (carbohydrates, proteins, fats) occurs in the
small intestine.
8. What is the primary function of the hormone leptin?
