A glandular organ associated with the digestive system that secretes digestive enzymes in the small intestine as well as a number of hormones including insulin and glucagon that are secreted into the bloodstream. It is thus part of the digestive and endocrine systems in vertebrates. The pancreas is formed from the entoderm initially as a dorsal and ventral bud that then fuse together to form a single organ. Both insulin and glucagon are already evident in the fetal blood stream by four to five months after conception.