Human digestive system gland in the digestive system. It is both an endocrine gland and an exocrine gland. The endocrine part secretes insulin when the blood sugar becomes high; insulin moves glucose from the blood into the muscles and other tissues for use as energy. The endocrine part releases glucagon when the blood sugar is low; glucagon allows stored sugar to be broken down into glucose by the liver in order to re-balance the sugar levels. The pancreas produces and releases important digestive enzymes in the pancreatic juice that it delivers to the duodenum. The pancreas lies below and at the back of
Uropygial gland nine families of birds lack a uropygial gland, mostly the ones unable to fly or the ones that produce powder down for feather maintenance. These include kiwis ("Apterygidae"), emu ("Dromaiidae"), ostriches ("Struthionidae"), rheas ("Rheidae"), cassowaries ("Casuariidae"), mesites ("Mesitornithidae"), bustards ("Otididae"), pigeons and doves ("Columbidae"), amazon parrots ("Psittacidae"), frogmouths ("Podargidae"), and woodpeckers ("Picidae"). These birds typically find other means to stay clean and dry, such as taking a dust bath. Researchers have been unable to correlate the presence or absence of the uropygial gland with factors such as distribution, climate, ecology, or flightlessness. The uropygial gland secretes an oil (preen oil)