Do the cardiac glands exist? 7. The cow

Area of Science:

• Veterinary Anatomy
• Gastrointestinal Histology
• Comparative Gastric Physiology

Background:

• The abomasal region near the omasum in cows has been historically misidentified as containing cardiac glands.
• Previous assertions regarding the presence of cardiac glands in the bovine stomach require histological and histochemical validation.

Purpose of the Study:

• To investigate the histological and histochemical characteristics of glands in the cow's abomasum, adjacent to the omasum.
• To determine if these glands are indeed cardiac glands or represent a different gastric structure.

Main Methods:

• Histological examination of abomasal gland tissues.
• Histochemical staining, including Periodic Acid-Schiff (PAS) and Alcian Blue (AB) at different pH levels (0.5 and 2.5).
• Analysis of glandular cell composition, including parietal cells and pepsinogen granule distribution.

Main Results:

• Glandular cells, excluding parietal cells, showed strong reactivity to PAS, AB (pH 2.5), and PAS-AB (pH 2.5) stains.
• Presence of fine pepsinogen granules and parietal cells indicated undifferentiated gastric glands, refuting the existence of cardiac glands in cows.
• Substances positive for PAS and AB staining decreased with cell differentiation, remaining in mucous neck cells and immature chief cells.

Conclusions:

• The so-called cardiac glands in the cow stomach do not exist; the region contains undifferentiated gastric glands.
• Mature chief cells contain coarse pepsinogen granules, distinct from the finer granules in mucous neck and immature chief cells.
• Parietal cells are numerous in the cow stomach, and the area with undifferentiated gastric glands is notably narrow.