Organ system

The nervous system in its place in the body

An organ system is a group of organs that work together as a biological system to perform one or more functions. Each organ does a particular job in the body, and is made up of distinct tissues.

Organs systems and their functions

There are eleven distinct organ systems in human beings, which form the basis of anatomy. Other animals have similar organ systems, although simpler animals may have fewer organs in an organ system or even fewer organ systems. Plants too have organs, such as flowers and leaves, and these are grouped into organ systems as well.

Organ System	Description	Component Organs
Respiratory system	breathing: exchange of oxygen and carbon dioxide	nose, mouth, sinus, pharynx, larynx, trachea, bronchi, lungs and diaphragm.
Digestive system	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
Cardiovascular system	circulate blood in order to transport nutrients, waste, hormones, O2, CO2, and aid in maintaining pH and temperature	blood, heart, arteries, veins, capillaries
Urinary system	maintain fluid and electrolyte balance, purify blood and excrete liquid waste (urine)	kidneys, ureters, bladder and urethra
Integumentary system	exterior protection of body and thermal regulation	skin, hair, exocrine glands, fat, and nails
Skeletal system	structural support and protection, production of blood cells	bones, cartilage, ligaments and tendons.
Muscular system	movement of body, production of heat	skeletal muscles, smooth muscles and cardiac muscle
Endocrine system	communication within the body using hormones made by endocrine glands	hypothalamus, pituitary, pineal gland, thyroid, parathyroid and adrenal glands, ovaries, testes
Lymphatic system	return fluids (lymph) to blood stream, aid immune responses, form white blood cells	lymph, lymph nodes, lymph vessels, tonsils, spleen, thymus
Nervous system	sensing and processing information, controlling body activities	brain, spinal cord, nerves, sensory organs (e.g. vision, smell, taste, hearing)
Reproductive system	sex organs involved in reproduction	ovaries, fallopian tubes, uterus, vagina, mammary glands, penis, testes, vas deferens, seminal vesicles and prostate

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 as it is not composed of organs.

Some organs are in more than one system. For example, the nose is in both the respiratory system and also is a sensory organ in the nervous system. The testes and ovary are both part of the reproductive systems and endocrine systems.