,NU 545 Physio-Pathological Basis of Advanced
Nursing Unit 6 Exam Study Guide University of
South Alabama Exam Prep & 100 Q&A MCQs
2026/2027
1. A graduate nursing student is reviewing the enteric nervous system. Which nerve plexus is
located between the inner circular and outer longitudinal muscle layers of the GI tract?
A. Submucosal (Meissner) plexus
B. Myenteric (Auerbach) plexus
C. Subserosal plexus
D. Mucosal plexus
Correct Answer: B
Rationale: The myenteric (Auerbach) plexus is located between the inner circular and outer
longitudinal muscle layers (tunica muscularis) of the GI tract. It primarily controls GI motility.
The submucosal (Meissner) plexus is located in the submucosa and regulates blood flow,
secretion, and absorption.
2. Which intrinsic nerve plexus of the GI tract is primarily responsible for regulating motility
reflexes, blood flow, absorption, secretions, and immune responses?
A. Submucosal plexus
B. Myenteric plexus
,C. Enteric plexus
D. Vagus nerve
Correct Answer: C
Rationale: The enteric plexus comprises three nerve plexuses located in different layers of the GI
wall: the submucosal (Meissner), myenteric (Auerbach), and subserosal plexuses. These enteric
nerve circuits regulate motility reflexes, blood flow, absorption, secretions, and immune
responses.
3. The upper esophageal sphincter (cricopharyngeal muscle) serves which function?
A. Prevents regurgitation from the stomach
B. Prevents entry of air into the esophagus during respiration
C. Initiates carbohydrate digestion
D. Regulates bile secretion
Correct Answer: B
Rationale: The upper esophageal sphincter (cricopharyngeal muscle) prevents entry of air into
the esophagus during respiration. The lower esophageal sphincter (cardiac sphincter) prevents
regurgitation from the stomach.
4. Which enzyme initiates carbohydrate digestion in the mouth and stomach?
, A. Pepsin
B. Ptyalin (salivary alpha-amylase)
C. Lipase
D. Trypsin
Correct Answer: B
Rationale: Ptyalin (salivary alpha-amylase) is an enzyme secreted in saliva that initiates
carbohydrate digestion in the mouth and stomach. Pepsin digests proteins in the stomach;
lipase digests fats; trypsin digests proteins in the small intestine.
5. A nurse is reviewing the functions of saliva. Which of the following is a function of salivary
bicarbonate?
A. Initiates protein digestion
B. Neutralizes bacterial acids and prevents tooth decay
C. Emulsifies fats
D. Activates pepsinogen
Correct Answer: B
Rationale: Salivary bicarbonate sustains a pH of about 7.4, which neutralizes bacterial acids and
prevents tooth decay. Saliva also contains mucus, sodium, chloride, potassium, and salivary
alpha-amylase (ptyalin).
Nursing Unit 6 Exam Study Guide University of
South Alabama Exam Prep & 100 Q&A MCQs
2026/2027
1. A graduate nursing student is reviewing the enteric nervous system. Which nerve plexus is
located between the inner circular and outer longitudinal muscle layers of the GI tract?
A. Submucosal (Meissner) plexus
B. Myenteric (Auerbach) plexus
C. Subserosal plexus
D. Mucosal plexus
Correct Answer: B
Rationale: The myenteric (Auerbach) plexus is located between the inner circular and outer
longitudinal muscle layers (tunica muscularis) of the GI tract. It primarily controls GI motility.
The submucosal (Meissner) plexus is located in the submucosa and regulates blood flow,
secretion, and absorption.
2. Which intrinsic nerve plexus of the GI tract is primarily responsible for regulating motility
reflexes, blood flow, absorption, secretions, and immune responses?
A. Submucosal plexus
B. Myenteric plexus
,C. Enteric plexus
D. Vagus nerve
Correct Answer: C
Rationale: The enteric plexus comprises three nerve plexuses located in different layers of the GI
wall: the submucosal (Meissner), myenteric (Auerbach), and subserosal plexuses. These enteric
nerve circuits regulate motility reflexes, blood flow, absorption, secretions, and immune
responses.
3. The upper esophageal sphincter (cricopharyngeal muscle) serves which function?
A. Prevents regurgitation from the stomach
B. Prevents entry of air into the esophagus during respiration
C. Initiates carbohydrate digestion
D. Regulates bile secretion
Correct Answer: B
Rationale: The upper esophageal sphincter (cricopharyngeal muscle) prevents entry of air into
the esophagus during respiration. The lower esophageal sphincter (cardiac sphincter) prevents
regurgitation from the stomach.
4. Which enzyme initiates carbohydrate digestion in the mouth and stomach?
, A. Pepsin
B. Ptyalin (salivary alpha-amylase)
C. Lipase
D. Trypsin
Correct Answer: B
Rationale: Ptyalin (salivary alpha-amylase) is an enzyme secreted in saliva that initiates
carbohydrate digestion in the mouth and stomach. Pepsin digests proteins in the stomach;
lipase digests fats; trypsin digests proteins in the small intestine.
5. A nurse is reviewing the functions of saliva. Which of the following is a function of salivary
bicarbonate?
A. Initiates protein digestion
B. Neutralizes bacterial acids and prevents tooth decay
C. Emulsifies fats
D. Activates pepsinogen
Correct Answer: B
Rationale: Salivary bicarbonate sustains a pH of about 7.4, which neutralizes bacterial acids and
prevents tooth decay. Saliva also contains mucus, sodium, chloride, potassium, and salivary
alpha-amylase (ptyalin).
