An organ system is a biological system consisting of a group of organs that work together to perform one or more functions.[1] Each organ has a specialized role in a organism body, and is made up of distinct tissues.
Other animals have similar organ systems to humans although simpler animals may have fewer organs in an organ system or even fewer organ systems.
There are 11 distinct organ systems in human beings,[2] which form the basis of human anatomy and physiology. The 11 organ systems: the respiratory system, digestive and excretory system, circulatory system, urinary system, integumentary system, skeletal system, muscular system, endocrine system, lymphatic system, nervous system, and reproductive system. There are other systems in the body that are not organ systems—for example, the immune system protects the organism from infection, but it is not an organ system since it is not composed of organs. Some organs are in more than one system—for example, the nose is in the respiratory system and also serves as a sensory organ in the nervous system; the testes and ovaries are both part of the reproductive and endocrine systems.
| Organ system | Description | Component organs | |
|---|---|---|---|
| breathing: exchange of oxygen and carbon dioxide | nose, mouth, paranasal sinuses, pharynx, larynx, trachea, bronchi, lungs and thoracic diaphragm | ||
| digestion breakdown and absorption of nutrients, excretion of solid wastes | teeth, tongue, salivary glands, esophagus, stomach, liver, gallbladder, pancreas, small intestine, large intestine, rectum and anus | ||
| circulate blood in order to transport nutrients, waste, hormones, O2, CO2, and aid in maintaining pH and temperature | blood, heart, arteries, veins and capillaries | ||
| maintain fluid and electrolyte balance, purify blood and excrete liquid waste (urine) | kidneys, ureters, bladder and urethra | ||
| exterior protection of body and thermal regulation | skin, hair, fat and nails | ||
| structural support and protection, production of blood cells | bones, cartilage, ligaments and tendons | ||
| movement of body, production of heat | skeletal muscles, smooth muscles and cardiac muscle | ||
| communication within the body using hormones made by endocrine glands | hypothalamus, pituitary, pineal gland, thyroid, parathyroid and adrenal glands, ovaries and testicles | ||
| various functions including lubrication and protection | ceruminous glands, lacrimal glands, sebaceous glands and mucus | ||
| return lymph to the bloodstream, aid immune responses, form white blood cells | lymph, lymph nodes, lymph vessels, tonsils, spleen and thymus | ||
| sensing and processing information, controlling body activities | brain, spinal cord, nerves, sensory organs and the following sensory systems (nervous subsystems): visual system, olfactory system, taste (gustatory system) and hearing (auditory system) | ||
| sex organs involved in reproduction | ovaries, fallopian tubes, uterus, vagina, vulva, penis, testicles, vasa deferentia, seminal vesicles and prostate |
Plants have two major organs systems. Vascular plants have two distinct organ systems: a shoot system, and a root system. The shoot system consists stems, leaves, and the reproductive parts of the plant (flowers and fruits). The shoot system generally grows above ground, where it absorbs the light needed for photosynthesis. The root system, which supports the plants and absorbs water and minerals, is usually underground.[3]
| Organ system | Description | Component organs | |
|---|---|---|---|
| anchors plants into place, absorbs water and minerals, and stores carbohydrates | roots | ||
| stem, leaves, and flowers |