Anatomy Exam Upper Gastrointestinal Tract 4 — Questions and Answers
Question 1: Which structure guards the outlet of the stomach, regulating chyme entry into the duodenum?
- Ileocecal valve
- Lower esophageal sphincter
- Pyloric sphincter (Correct answer)
- Sphincter of Oddi
Correct answer: Pyloric sphincter
The pyloric sphincter is a thickening of circular smooth muscle at the gastroduodenal junction that controls the rate of gastric emptying.
Question 2: The left gastric vein (coronary vein) drains into which vessel?
- Inferior vena cava
- Superior mesenteric vein
- Portal vein (Correct answer)
- Splenic vein
Correct answer: Portal vein
The left gastric vein drains directly into the portal vein and is clinically important because it communicates with esophageal veins — a site of portosystemic anastomosis.
Question 3: Which of the following correctly describes the position of the stomach's cardia?
- Posterior to the xiphoid process at T7
- Left of the midline at T11 (Correct answer)
- Right of the midline at L1
- Anterior to the aortic hiatus at T12
Correct answer: Left of the midline at T11
The cardia (gastroesophageal junction) lies to the left of the midline at the level of T11, just below the esophageal hiatus.
Question 4: Brunner's glands, which secrete alkaline mucus to protect against acid chyme, are located in which layer of the duodenum?
- Mucosa
- Submucosa (Correct answer)
- Muscularis externa
- Serosa
Correct answer: Submucosa
Brunner's glands are submucosal glands found predominantly in the first and second parts of the duodenum, distinguishing it histologically from the jejunum.
Question 5: The celiac trunk arises from the abdominal aorta at which vertebral level?
- T12
- L1 (Correct answer)
- L2
- L3
Correct answer: L1
The celiac trunk arises from the anterior surface of the abdominal aorta at the level of L1 and immediately branches into the left gastric, splenic, and common hepatic arteries.
Question 6: Which plexus of Auerbach regulates the muscular contractions of the GI wall?
- Submucosal (Meissner's) plexus
- Myenteric (Auerbach's) plexus (Correct answer)
- Celiac plexus
- Hypogastric plexus
Correct answer: Myenteric (Auerbach's) plexus
The myenteric (Auerbach's) plexus lies between the inner circular and outer longitudinal smooth muscle layers and primarily controls GI motility.
Question 7: Intrinsic factor, essential for vitamin B12 absorption, is secreted by which gastric cell type?
- G cells
- D cells
- Chief cells
- Parietal cells (Correct answer)
Correct answer: Parietal cells
Parietal cells secrete both HCl and intrinsic factor; intrinsic factor binds B12 in the stomach and the complex is absorbed in the terminal ileum.
Anatomy Exam Upper Gastrointestinal Tract 4
Which structure guards the outlet of the stomach, regulating chyme entry into the duodenum?