what is the top part of a birds stomach called
Bird anatomy The avian stomach is composed of two organs, the proventriculus and the gizzard that work together during digestion. The proventriculus is a rod shaped tube, which is found between the esophagus and the gizzard, that secretes hydrochloric acid and pepsinogen into the digestive tract.[52] The acid converts the inactive pepsinogen into the active proteolytic enzyme, pepsin, which breaks down specific peptide bonds found in proteins, to produce a set of peptides, which are amino acid chains that are shorter than the original dietary protein.[53][54] The gastric juices (hydrochloric acid and pepsinogen) are mixed with the stomach contents through the muscular contractions of the gizzard.[55]