Organs are
collections of tissues that are joined in a structural unit with purpose of
serving a common function. They consist of main tissue which is called
parenchzma and sporadic tissues that are called stroma. For a specific organ,
the main tissue is the one that is unique for the specific organ, while sporadic
tissues include nerves, blood and connective tissues. Functionally related
organs often cooperate to form whole organ systems.
Organs exist in all
higher biological organisms, in particular they are not restricted to animals,
but they can also be identified in plants. Single-cell organisms, like
bacteria, the functional analogues of organs are called organelles. A hollow
organ is a visceral organ that is a hollow tube or pouch, such as the stomach
or intestine, or that includes a cavity, like the heart or urinary bladder.
Some organs in the
body includes: adrenal
glands, anus, appendix, bladder, bones, bronchi, ears, oesophagus eyes, gall
bladder, genitals, heart, hypothalamus, larynx, liver, lungs, large intestine, lymph
nodes, meninges, mouth, nose, pancreas, parathyroid glands, pituitary
gland, rectum, salivary glands, skin, skeletal muscles, small intestine, spinal
cord, stomach, thymus gland, thyroid, tongue, trachea, ureters, urethra. The
Main ones includes: kidney, Liver, Gall Bladder, Pancreas, Small
Intestines/Duodenum, Stomach, Collin, Rectum, Large Intestines, Heart, lungs, spleen
and brain.