What is a primary function of the omasum?

• A. Water absorption and particle size reduction.
• B. Hydrolysis of proteins.
• C. Digestive enzyme production.
• D. Gastric acid secretion.

Answer: (C)

The omasum’s main job is to finish preparing the ingested material for the true digestion that happens deeper in the stomach. Its many leaf-like folds act like a grinder and a filter, so mechanical reduction of particle size continues as the digesta passes through. At the same time, the omasum absorbs water (and some dissolved minerals and volatile fatty acids) from the ingesta, helping to concentrate and regulate what moves on to the abomasum. It does not produce digestive enzymes, nor does it secrete gastric acid—those functions belong to other parts of the digestive system (enzymes from the pancreas and intestinal lining, acid from the abomasum). So the primary function is water absorption together with particle size reduction.