Gastric glands

Gastric glands are tubular glands located within the mucosa of the stomach. They open into the base of the gastric pits and are responsible for secreting gastric juice, enzymes, acid, mucus, and hormones essential for digestion.

Types of Gastric Glands

Histological Appearance of a Fundic Gland

Parts of gastric gland, from superficial to deep (from lumen to the outside), include:

• Gastric pit

• Isthmus

• Neck

• Base

Cells of fundic (oxyntic) glands

1. Mucous neck cells

These are located in the neck of the gland. They secrete thin mucus which helps protect the gastric mucosa.

2. Parietal (oxyntic) cells

These are largely eosinophilic cells. They are predominantly located in the upper half of the gland and secrete:

• Hydrochloric acid (HCl)

• Intrinsic factor (required for vitamin B12 absorption in the terminal ileum)

3. Chief cells

These are located mainly in the deeper part of the gland (towards the base region). They are basophilic due to abundant rough endoplasmic reticulum (that contains ribosomes).

The chief cells secrete:

• Pepsinogen → converted to pepsin in acidic conditions.

• Gastric lipase

4. Enteroendocrine cells

These are scattered throughout the gastric glands and secrete hormones and paracrine factors (gastrin, somatostatin, histamine, serotonin).

5. Stem Cells

These are located in the isthmus/neck region and serve to continuously replace gastric epithelial cells.

Cell distribution

• Surface & pit → contains surface mucous cells

• Neck → contains mucous neck cells and parietal cells

• Base → contains chief cells and enteroendocrine cells

Functions of Gastric Glands

• Production of gastric acid for digestion and antimicrobial activity.

• Secretion of pepsinogen for protein digestion.

• Production of intrinsic factor for vitamin B12 absorption.

• Secretion of mucus and bicarbonate for mucosal protection.

• Release of hormones regulating gastric motility and secretion.

Clinical correlates

• Pernicious anaemia: Autoimmune destruction of parietal cells results in loss of intrinsic factor that leads to vitamin B12 deficiency and megaloblastic anaemia.

• Peptic ulcer disease could result from disruption of the mucosal barrier and acid peptic injury.

• Atrophic gastritis could lead to loss of gastric glands and glandular atrophy, which is associated with reduced acid secretion and increased gastric cancer risk.