Pylorus Flashcards

Examine the pylorus, including its antrum, canal, muscular sphincter, vascular supply, innervation, and role in gastric emptying.

Card 1 of 30Question

What is the pyloric part of the stomach?

The distal region of the stomach that connects the gastric body to the duodenum.

In This Section

1. What is the pyloric part of the stomach?

The distal region of the stomach that connects the gastric body to the duodenum.

2. What are the two principal subdivisions of the pyloric part?

The pyloric antrum and pyloric canal.

3. Which anatomical landmark indicates the beginning of the pyloric part along the lesser curvature?

The angular incisure, also called the incisura angularis.

4. What is the pyloric antrum?

The wider proximal portion of the pyloric region that leads into the narrower pyloric canal.

5. What is the pyloric canal?

The narrow distal passage connecting the pyloric antrum to the pyloric orifice.

6. What is the pyloric orifice?

The opening between the stomach and the superior first part of the duodenum.

7. At approximately which vertebral level is the pylorus located in the supine position?

L1, near the transpyloric plane, although its position varies with posture and gastric filling.

8. Which anatomical structure surrounds the pyloric orifice?

The pyloric sphincter.

9. Which muscular layer forms the pyloric sphincter?

A marked thickening of the inner circular smooth muscle layer of the muscularis externa.

10. What is the principal function of the pyloric sphincter?

Regulating the passage of gastric contents into the duodenum.

11. How does the pyloric sphincter help limit duodenogastric reflux?

Its tonic contraction restricts the backward movement of duodenal contents into the stomach.

12. What role does the pyloric antrum play in mechanical digestion?

It generates strong contractions that mix and grind gastric contents before emptying.

13. What is gastric retropulsion?

The backward movement of chyme into the antrum when contractions encounter a narrowed pyloric opening.

14. Which gastric glands predominate in the pyloric mucosa?

Pyloric glands, consisting mainly of mucus-secreting cells and enteroendocrine cells.

15. Which enteroendocrine cells in the pyloric antrum secrete gastrin?

G cells.

16. What is the principal effect of gastrin released from the pyloric antrum?

Stimulation of gastric acid secretion, mainly through enterochromaffin-like cells and parietal cells.

17. Which pyloric enteroendocrine cells secrete somatostatin?

D cells.

18. What is the function of somatostatin in the pyloric antrum?

It inhibits gastrin release and helps regulate gastric acid secretion.

19. Which artery commonly supplies the pyloric region along the lesser curvature?

The right gastric artery, usually arising from the proper hepatic artery.

20. Which artery supplies the pyloric region along the greater curvature?

The right gastro-omental artery, arising from the gastroduodenal artery.

21. Which small arterial branch may cross the anterior surface of the pylorus?

The prepyloric artery, commonly a branch of the right gastric artery.

22. Into which venous system does blood from the pylorus ultimately drain?

The hepatic portal venous system through gastric and gastro-omental venous tributaries.

23. Which lymph nodes commonly receive lymphatic drainage from the pyloric region?

The pyloric and right gastric lymph nodes, with subsequent drainage toward hepatic and celiac nodes.

24. Which nerves provide parasympathetic innervation to the pyloric region?

Gastric branches of the anterior and posterior vagal trunks.

25. Which terminal vagal branches supply the pyloric antrum?

The crow's foot branches of the nerves of Latarjet.

26. Which autonomic plexus provides sympathetic fibers to the pylorus?

The celiac plexus through periarterial nerve pathways.

27. What is infantile hypertrophic pyloric stenosis?

Hypertrophy of pyloric circular smooth muscle causing narrowing of the gastric outlet.

28. Why does hypertrophic pyloric stenosis typically cause nonbilious vomiting?

The obstruction lies proximal to the entry of bile into the descending duodenum.

29. What is a pyloromyotomy?

Surgical division of the hypertrophied pyloric muscle to relieve gastric outlet obstruction.

30. What is pyloroplasty?

Surgical enlargement of the pyloric channel to facilitate gastric emptying.