Organ (anatomy)

Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)

In biology, an organ (Latin: organum, "instrument, tool") is a group of tissues that perform a specific function or group of functions. Common animal organs include the heart, lungs, brain, eye, stomach, spleen, pancreas, kidneys, liver, intestines, skin, uterus, bladder, bone, etc. A group of related organs is an organ system.

Organelles are analogous sub-cellular structures.

Organ systems[]

There are eleven major organ systems found in mammals.

Mammals such as humans have a variety of organ systems. These specific systems are also widely studied in human anatomy.

Circulatory system: pumping and channeling blood to and from the body and lungs with heart, blood and blood vessels.
Digestive system: digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, colon, rectum and anus.
Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary or pituitary gland, pineal body or pineal gland, thyroid, parathyroids and adrenals, i.e., adrenal glands.
Excretory system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine.
Immune System: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the Immune system: defending against disease-causing agents with leukocytes, tonsils, adenoids, thymus and spleen.
Integumentary system: skin, hair and nails.
Muscular system: movement with muscles.
Nervous system: collecting, transferring and processing information with brain, spinal cord and nerves.
Reproductive system: the sex organs, such as ovaries, fallopian tubes, uterus, vagina, mammary glands, testes, vas deferens, seminal vesicles, prostate and penis.
Respiratory system: the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm.
Skeletal system: structural support and protection with bones, cartilage, ligaments and tendons.