Here we have an image of a parrot with its insides out! It is a not actually a budgie but the details are the same so we can use it to explore the budgie internal organs, and get a better understanding of our budgies and how they function.
Here is a brief description of budgie internal organs and their uses:
cloaca - the organ used to excrete waste and to transfer semen during mating. coracoid - an important bone, part of a structure vital to flight. crop - a simple sack that holds the food your budgie has swallowed until it is passed slowly down to be digested. duodenum - the first part of the small intestine, helps digest food. ear - yes, it an ear... for hearing with... gizzard - a tough walled, muscular sack that fills with small stones/insoluble grit. Once the food reaches here it is crushed and rolled around with with grit until it is broken down enough to be passed into the intestines for absorption. The gizzard does the same job for your budgie that your teeth do for you. heart - pumps the blood around, just like yours does. kidney - carries out many vital functions including removing waste and toxins to be excreted as uric acid. liver - a vital organ that has many functions including producing hormones, and bile for digestion. lung - transfers oxygen from the air into the blood stream. oesophagus - the tube that carries the food from the budgies mouth to its crop. pectoral muscles - the large chest muscles used to flap the wings. proventriculus - a glandular part of the stomach that mixes digestive enzymes with the food before it enters the gizzard. ribs - surround the birds chest to protect the important organs such as the heart and lungs. small intestine - continues the digestion of food and absorbs most of the nutrients from the food. testis - produces sperm. tongue - used for tasting and manipulating food... and toys! trachea - the tube that carries air to and from the lungs whilst breathing. ureter - carries uric acid from the kidneys to the cloaca. vas deferens - a tube for transporting semen from the testes to the cloaca during mating. vent - external parts ofthe cloaca, effectively the same organ.