Anatomy: Animals InsideOrgans and Organ Systems |
What is an organ system? |
An organ system is a group of organs working together to perform a vital body function. The vast majority of vertebrate animals have twelve major organ systems; the following lists those systems, their components, and their functions:
Organ System |
Components |
Functions |
Cardiovascular |
Heart, blood, and blood vessels |
Transports blood throughout the body, and circulatory system, supplying nutrients and carrying oxygen to the lungs and wastes to kidneys |
Digestive |
Mouth, esophagus, stomach, intestines, liver, gallbladder, and pancreas |
Ingests food and breaks it down into smaller chemical units |
Endocrine |
Pituitary, adrenal, thyroid, and other ductless glands |
Coordinates and regulates the activities of the body |
Immune |
Lymphocytes, antibodies; macrophages, and also thymus, tonsils and spleen |
Removes foreign substances; fights diseases |
Integumentary |
Skin, hair, nails, and sweat glands |
Protects the body |
Lymphatic |
Lymph nodes, lymphatic capillaries, lymphatic vessels, spleen, and thymus |
Captures fluid and returns it to the cardiovascular system |
Muscular |
Skeletal muscle, cardiac muscle, and smooth muscle |
Allows body movements |
Nervous |
Nerves, sense organs, brain, and spinal cord |
Receives external stimuli, processes information, and directs activities |
Reproductive |
Testes, ovaries, and related organs |
Carries out reproduction |
Respiratory |
Lungs, trachea, and other air passageways |
Exchanges gases–captures oxygen (O2) and disposes of carbon dioxide (CO2) |
Skeletal |
Bones, cartilage, ligaments, tendons |
Protects the body and provides support for locomotion and movement |
Urinary (or Excretory) |
Kidneys, ureters, bladder, and urethra |
Fluid balance, excretion of urine; removes wastes from the bloodstream |
Vestibular |
Ear system |
Contributes to balance and special orientation |