Prostomach

In Ruminants the Proventriculus is the Forestomach, divided into three compartments: Rumen. Reticulum, and Omasum. The term Ruminoreticulum is required by the morphological and physiological unity of the two compartments.

In birds, the proventriculus is a glandular part of the stomach located between the esophagus and the gizzard. The proventriculus is responsible for secreting digestive enzymes and hydrochloric acid, which initiate the breakdown of food before it passes into the gizzard for mechanical digestion.