Anatomy: Animals Inside

Organs and Organ Systems

What is an organ?

An organ is a group of several different tissues working together as a unit to perform a specific function or functions. Each organ performs functions that none of the component tissues can perform alone, with this cooperative interaction of different tissues being a basic feature of animals. The heart is an example of an organ: It consists of cardiac muscle wrapped in connective tissue; heart chambers, which are lined with epithelium tissue; and nerve tissue, which controls the rhythmic contractions of the cardiac muscles.


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