Physiology of Ruminant Stomach The ruminant stomach is composed of four compartments: rumen, reticulum, omasum, and abomasum. The rumen allows mechanical, chemical, and microbial simplification of food through fermentation by microorganisms. The reticulum traps foreign bodies in the ingesta and assists in food breakdown. Omasum absorbs water from the ingesta and grinds food while absorbing volatile fatty acids (VFAs) and minerals.
Functions of Abomasum Abomasum is the glandular portion that secretes hydrochloric acid for digestion along with pepsinogen activation to pepsin; it also releases gastric lipase for lipid hydrolysis. Intrinsic factor aids vitamin B12 absorption while pyloric gastrin stimulates pancreatic secretions release.
Physiology of Non-Ruminant Stomach The non-ruminants' stomach has a proximal region for storage with weak continuous contractions propelling food to distal grinding region where peristalsis occurs before selective passage through pylorus into duodenum; inter-digestive motility complex clears indigestible particles between meals without causing fermentation.