Histology of the Hollow Digestive System

Question 1

Click on Answer to view histological slides of the stomach.

Answer 1

[Slide 1] [Slide 2] [Slide 3]

Question 2

What type of glands are the principal gastric glands in terms of anatomical organisation?

Answer 2

branched tubular glands

Question 3

Name five types of cells present in gastric glands and state the function and morphology of each.

Answer 3

(a) Chief cells: [also called peptic cells/zymogen cells]. They are particularly numerous in the basal part of the gland. They are protein secreting cells, hence their cytoplasm is mainly basophilic, which can be accounted for by the abundance of RER, especially in the basal part. In the apical part of the cytoplasm are secretory granules that are weakly acidophilic. These granules contain pepsinogen. The luminal surface of these cells bear small irregular microvilli.

(b) Parietal/oxyntic cells: These cells occur mainly in the neck region of the gastric glands. They secrete hydrochloric acid and intrinsic factor. The cytoplasm of these cells stains intensely and uniformly with eosin.

(c) Mucous neck cells: These cells are located just below the gastric pits, interspersed with the parietal cells. These are large cells with a clear cytoplasm. The nucleus is flattened and pushed to the base of the cell by the accumulated mucous granules.

(d) Endocrine/argentaffin cells: Endocrine cells are scattered, usually solitary, throughout the epithelium of the gastrointestinal tract. The best-characterized endocrine cells in the gastric mucosa are gastrin-producing cells (G cells) and somatostatin producing cells (D cells).
D cells are found mainly in the pyloric antrum. They inhibit G cells and thereby acid production. D cell function is stimulated by acid in the lumen of the stomach and duodenum.

Question 4

Giving a reason, identify the part of the gastrointestinal tract displayed: [Slide].

Answer 4

Duodenum: presence of mucous glands [Brunner’s glands] below the muscularis mucosae

Question 5

Identify the structures circled in red: [Slide].

Answer 5

Peyer’s patches

Question 6

Giving a reason, identify the slide: [Slide].

Answer 6

Gastroduodenal junction
(1) presence of Brunner’s glands in the submucosa on the duodenal side, and presence of pyloric glands in the mucosa on the gastric side [the latter part is not apparent in the image provided but it is the case]
(2) presence of villi on the duodenal side and presence of gastric pits on the gastric side

Further images: [Diagram] [Slide 2]

Question 7

Giving a reason, identify the slide: [Slide].

Answer 7

Gastroesophageal junction
Abrupt transition from stratified squamous epithelium to simple columnar epithelium

Further images: [Slide 2] [Slide 3] [Slide 4]

Question 8

(a) Name the nerve plexus present in the submucosa of the stomach wall.
(b) What is one characteristic feature of the submucosa of the stomach wall.

Answer 8

(a) Meissner’s nerve plexus
(b) It has no glands.

Question 9

List 7 gastric protective mechanisms.

Answer 9

✓ Digestive secretions [survived by typhoid and other bacilli, eggs of parasites and by Helicobacter pylori]
✓ Mucous and bicarbonate outer coating of the epithelium
✓ A film of surfactant-like lipid secreted by the epithelium
✓ Regenerative power of the epithelium, by cell proliferation and migration
✓ Lymphoid nodules and lymphocytes, other leucocytes in the mucosa and submucosa
✓ Tight junctions between epithelial cells
✓ Vomiting

Question 10

Giving a reason, identify the organ: [Slide].

Answer 10

Colon: presence of taenia coli
Also see: [Slide 2]