Organ

An organ is a group of tissues of a lifeform that perform a specific function or group of functions. Healthy organs are required to sustain the life of a being – organ failure, such as that brought on by an accelerated rate of cellular decay, would ultimately result in death. 

Apollo had an extra organ in his chest with a function that was unclear to Doctor McCoy, though Captain Kirk hypothesized it allowed Apollo to access and wield a powerful field of energy. 

Some members of the Zalkonian species had the ability to regenerate damaged organs. The injured Zelkonian referred to as "John Doe" was able to regenerate most of his damaged organs in less than thirty-six hours while in a emergency bio-support unit in the USS Enterprise (NCC-1701-D)'s sickbay. 

Takarans had a very unusual anatomy and physiology where their internal organs were not as distinct as those of most humanoids – their organ systems were equally distributed throughout the body, making them resistant to most injuries. 

The Phage, a disease that afflicted the Vidiians, devoured the organs and tissues of those it infected. Many Vidiians survived in the short term by making extensive use of transplantation and organ piracy, sometimes using bio-probes to steal healthy organs from those unaffected by the disease. 

While in a telepathically-induced coma in 2371, Doctor Bashir imagined that he was experiencing accelerated aging. In this reality, Quark was taking wagers at his bar on things such as which of Bashir's organs would fail first or when he would end up dying. 

Synthetic organs were sometimes used in battlefield situations, though Doctor Bashir commented how it was difficult knowing what organs to keep on hand. Bashir claimed that the Holy Grail of organ replacement would be to come up with a way to inject the patient with undifferentiated tissue that could become whatever organ is needed. 

Animal organs

 * Bones of the skeletal system
 * Brain
 * Ear
 * Eye
 * Hair
 * Heart
 * Intestines
 * Kidney
 * Liver
 * Lungs
 * Pancreas
 * Sexual organs
 * Ovaries
 * Uterus
 * Skin
 * Stomach
 * Tongue

Plant organs

 * Flower
 * Fruit
 * Leaf
 * Root
 * Seed