Organ (anatomy)
In
biology, an
organ (
Latin:
organum, "instrument, tool") is a group of
tissues that perform a specific function or group of functions. Usually there is a
main tissue and
sporadic tissues. The main tissue is the one that is unique for the specific organ. For example, main tissue in the
heart is the
myocard, while sporadic are the
nervous,
blood,
connective etc.
Common
animal (including
human) organs include the
heart,
lungs,
brain,
eye,
stomach,
spleen,
pancreas,
kidneys,
liver,
intestines,
skin,
uterus, and
bladder. Animal organs inside the
thorax or
abdomen are often referred to as
internal organs (this term is not used for organs inside the
head or other parts of the body). The internal organs collectively are often called
viscera, the plural of the rarely-used
viscus.
Many organs can be
transplanted from a healthy or recently deceased person to another with a diseased or damaged organ. Work is underway to allow some organs to be transplanted from other animals to humans (
xenotransplantation).
Plant organs can be divided into vegetative and reproductive. Vegetative plant organs are
root,
stem and
leaf, while reproductive are
flower,
seed and
fruit.
The vegetative organs are essential for maintaining the life of a plant (they do the vegetative, vital functions, like
photosynthesis), while the reproductive are essential in the
reproduction. But, if there is
asexual vegetative reproduction, the vegetative organs are those which create the new generation of plants, and therefore usually creating a
clonal colony.
A group of related organs is an
organ system. Organs within a system may be related in any number of ways, but relationships of function are most commonly used. For example the
urinary system comprises organs that work together to produce, store, and carry
urine.
The functions of organ systems often share significant overlap. For instance, the
nervous and
endocrine system both operate via a shared organ, the
hypothalamus. For this reason, the two systems are combined and studied as the
neuroendocrine system. The same is true for the
musculoskeletal system, which involves the relationship between the
muscular and
skeletal systems.
*
Organ transplant*
Organelles, analogous sub-
cellular structures.
