a fully differentiated structural and functional unit in an animal that is specialized for some particular function

internal organs collectively (especially those in the abdominal cavity)

an organ that separates waste substances from the blood and discharges them

large and complicated reddish-brown glandular organ located in the upper right portion of the abdominal cavity; secretes bile and functions in metabolism of protein and carbohydrate and fat; synthesizes substances involved in the clotting of the blood; synthesizes vitamin A; detoxifies poisonous substances and breaks down worn-out erythrocytes

the hollow muscular organ located behind the sternum and between the lungs; its rhythmic contractions move the blood through the body

an enlarged and muscular saclike organ of the alimentary canal; the principal organ of digestion