What Are the Internal Organs of the Human Body?
The human body is composed of millions of cells, myriad tissues, and numerous organs; some have unique functions, other functions are coordinated, and some functions overlap. Therefore, a classification of organ systems is not definitive. For example, the endocrine system releases hormones into the body, and the gastrointestinal tract digests food. The pancreas does both and may be classified into either of these systems. Likewise, the brain may also release hormones but is classified as part of the nervous system, though part of the brain, called the pituitary, could be called an endocrine organ.
