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]
Vein Veins are less muscular than arteries and are often closer to the skin. There are valves in most veins to prevent backflow.
Pectoralis minor The pectoralis minor (/ˌpɛktəˈreɪlɪs ˈmaɪnər/) is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major in the human body.
Aegyptopithecus Aegyptopithecus zeuxis has become one of the best known extinct primates based on craniodental and postcranial remains.[2]