Classification and localization
Based on their location and structural features, three types of gastric glands are distinguished:
- Proper (fundic) glands. Located in the fundus and body of the stomach. This is the most numerous group (about 35 million). Their terminal portions are practically unbranched, and their cellular composition is the most diverse.
- Cardiac glands. Located in the cardia. There are only 1–2 million of them, and their terminal portions are heavily branched.
- Pyloric glands. Located in the pyloric region (about 3.5 million). They have branched terminal portions with wide lumens. An important anatomical feature of this region is that the gastric pits here are 2–3 times deeper than in other parts of the stomach.
Cellular composition of proper glands
Structurally, each gland consists of an excretory duct (isthmus and neck) and the main part (body and fundus). The cell population of the proper glands includes several types of exocrinocytes and endocrinocytes:
- Parietal (oxyntic) cells. Responsible for the secretion of hydrogen and chloride ions (components of hydrochloric acid), as well as intrinsic factor (essential for vitamin B12 absorption). These are the largest cells of the gland, lying singly in the periphery. They are characterized by marked oxyntia (staining bright orange with congo red) and a huge number of mitochondria that provide energy for proton pumps.
- Chief cells. Synthesize the inactive enzyme pepsinogen, as well as chymosin. These cells are smaller, arranged in groups, and have a basophilic cytoplasm due to a well-developed protein-synthesis apparatus (rough endoplasmic reticulum and Golgi complex).
- Mucous neck cells (mucocytes). Produce a mucous secretion. They have dense nuclei displaced toward the basal pole and a light, reticular apical part.
- Neck cells. Located in the excretory ducts. In addition to neck mucous cells, poorly differentiated (stem) cells are found here. This is the cambial zone: from here, cells migrate upwards (rapidly renewing the surface epithelium every ~4 days) and downwards (slowly differentiating into glandular cells over months).
- Endocrine cells. In the proper glands, these are represented by EC, ECL, and A cells.
Mechanism of hydrochloric acid secretion
The production of hydrochloric acid (HCl) by parietal cells is a complex biochemical process. Inside the cell, the enzyme carbonic anhydrase converts carbon dioxide (delivered from the blood) and water into carbonic acid. It dissociates into bicarbonate and a proton (H+).
At the apical membrane, protons are pumped into the gastric lumen by H+,K+-ATPase (proton pump) in exchange for potassium ions (antiporter). Chloride ions (Cl-) enter the cell from the blood and are then secreted into the gland lumen along with potassium (symport). Due to the active export of acidic components, the cytoplasm of parietal cells becomes depleted of them, which causes its pronounced oxyntia under light microscopy. An important ultrastructural feature of such cells is the branched system of intracellular secretory canaliculi with microvilli.
Mucous cells and pyloric glands
Gastric mucous cells (mucocytes) are divided into three types: surface (surface epithelium), neck (in the ducts), and accessory/neck mucous cells (in the terminal portions).
In the cardiac and pyloric glands, it is the mucous cells (light cells with a flattened nucleus) that make up the bulk of the exocrinocytes. The pyloric glands are also distinguished by a specific endocrine apparatus: they contain G cells, which produce gastrin, as well as D, D1, and P cells.
Briefly: answers to topical questions
What hormones and biologically active substances are secreted by gastric endocrinocytes (EC, ECL, A, D)?
The specified gastric endocrinocytes secrete the following substances:
- EC cells — serotonin and melatonin (derivatives of the amino acid tryptophan).
- ECL cells — histamine (a derivative of the amino acid histidine); histamine is a potent stimulator of HCl secretion by parietal cells.
- A-like cells — gastric glucagon / enteroglucagon (polypeptide); its effect is similar to pancreatic glucagon — mobilization of glucose and fatty acids / energy from storage depots between meals.
The secretory products of D cells are not specified in the provided sources.
To remember what chief and parietal cells do, use this mnemonic: 'The CHIEF cook makes PEPSI (pepsinogen), while the OXYNTIC/LINING worker lays down ACID (hydrochloric acid) and a HARD HAT / CASTLE (intrinsic factor).'
Class and exam questions
Where are gastric stem cells located?
Undifferentiated (stem) cells are located in the neck of the glands. They provide both rapid renewal of the surface epithelium of the gastric pits (upward) and slow renewal of the gland cells themselves (downward).
Why are parietal cells oxyntic?
They actively secrete acidic components (protons and chloride ions) into the gastric lumen, causing their own cytoplasm to become alkalinized and acquire an affinity for acidic stains (oxyntia).
What else to study on this topic
- Endocrine system of the stomach (APUD system)
- Ultrastructure of secretory canaliculi in parietal cells
- The process of pepsinogen activation
- Hormonal regulation of secretion (the role of G cells)
Master the entire topic in the "Histology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on 'Gastric glands' and 3,485 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 137 video lessons on the subject
Other topics in the section "Digestive system: stomach and small intestine"
Free video lessons: histologyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.