A&P 1 101 Module 3 Exam - Digestive System Test -
Portage Learning | 2026/2027 Edition
EXACTLY 28 Questions | Verified Answers &
Rationales.
DOMAIN 1: ALIMENTARY CANAL ANATOMY & HISTOLOGY (Questions 1-10)
Q1. Which of the following represents the correct order of the four histological tunics of the
alimentary canal, starting from the innermost layer in contact with the lumen and moving
outward?
A. Serosa, Muscularis Externa, Submucosa, Mucosa
B. Mucosa, Submucosa, Muscularis Externa, Serosa [CORRECT]
C. Submucosa, Mucosa, Serosa, Muscularis Externa
D. Mucosa, Muscularis Externa, Submucosa, Serosa
Correct Answer: B
Rationale: The alimentary canal wall consists of four distinct tunics arranged concentrically.
The Mucosa is the innermost layer facing the lumen, followed by the Submucosa, then the
Muscularis Externa, and finally the outermost Serosa (or adventitia in some regions).
Q2. The innermost tunic of the alimentary canal, which lines the lumen and is responsible for
secretion and absorption, is the:
A. Submucosa
B. Muscularis externa
C. Serosa
D. Mucosa [CORRECT]
, Correct Answer: D
Rationale: The Mucosa is the innermost layer. It consists of an epithelial lining (often simple
columnar in the stomach/intestines), a lamina propria, and a muscularis mucosae. Its primary
functions are secretion of mucus/digestive enzymes and absorption of nutrients.
Q3. The submucosal plexus (Meissner's plexus) is a network of nerves located within which
specific layer of the alimentary canal?
A. Mucosa
B. Submucosa [CORRECT]
C. Muscularis externa
D. Serosa
Correct Answer: B
Rationale: As indicated by its name, the Submucosal plexus (Meissner's plexus) is found in the
Submucosa. It regulates glandular secretions and blood flow within the gut wall.
Q4. The muscularis externa layer of the small intestine typically consists of two layers of
smooth muscle. What is the specific orientation of these layers?
A. An outer circular layer and an inner longitudinal layer
B. An outer longitudinal layer and an inner circular layer [CORRECT]
C. An outer oblique layer and an inner circular layer
D. Two layers of longitudinal muscle only
Correct Answer: B
Rationale: In most of the alimentary canal, the Muscularis externa consists of an inner circular
layer and an outer longitudinal layer. The exception is the stomach, which has an additional
outer oblique layer.
Portage Learning | 2026/2027 Edition
EXACTLY 28 Questions | Verified Answers &
Rationales.
DOMAIN 1: ALIMENTARY CANAL ANATOMY & HISTOLOGY (Questions 1-10)
Q1. Which of the following represents the correct order of the four histological tunics of the
alimentary canal, starting from the innermost layer in contact with the lumen and moving
outward?
A. Serosa, Muscularis Externa, Submucosa, Mucosa
B. Mucosa, Submucosa, Muscularis Externa, Serosa [CORRECT]
C. Submucosa, Mucosa, Serosa, Muscularis Externa
D. Mucosa, Muscularis Externa, Submucosa, Serosa
Correct Answer: B
Rationale: The alimentary canal wall consists of four distinct tunics arranged concentrically.
The Mucosa is the innermost layer facing the lumen, followed by the Submucosa, then the
Muscularis Externa, and finally the outermost Serosa (or adventitia in some regions).
Q2. The innermost tunic of the alimentary canal, which lines the lumen and is responsible for
secretion and absorption, is the:
A. Submucosa
B. Muscularis externa
C. Serosa
D. Mucosa [CORRECT]
, Correct Answer: D
Rationale: The Mucosa is the innermost layer. It consists of an epithelial lining (often simple
columnar in the stomach/intestines), a lamina propria, and a muscularis mucosae. Its primary
functions are secretion of mucus/digestive enzymes and absorption of nutrients.
Q3. The submucosal plexus (Meissner's plexus) is a network of nerves located within which
specific layer of the alimentary canal?
A. Mucosa
B. Submucosa [CORRECT]
C. Muscularis externa
D. Serosa
Correct Answer: B
Rationale: As indicated by its name, the Submucosal plexus (Meissner's plexus) is found in the
Submucosa. It regulates glandular secretions and blood flow within the gut wall.
Q4. The muscularis externa layer of the small intestine typically consists of two layers of
smooth muscle. What is the specific orientation of these layers?
A. An outer circular layer and an inner longitudinal layer
B. An outer longitudinal layer and an inner circular layer [CORRECT]
C. An outer oblique layer and an inner circular layer
D. Two layers of longitudinal muscle only
Correct Answer: B
Rationale: In most of the alimentary canal, the Muscularis externa consists of an inner circular
layer and an outer longitudinal layer. The exception is the stomach, which has an additional
outer oblique layer.
