organ system

An organ system is a collection of organs that have related roles in an organism's functioning. Eleven major organ systems are present within humans and animals, although some animals lack one or more of them. They are:


  • skeletal system
  • muscular system
  • integumentary system (skin)
  • nervous system
  • digestive system
  • excretory system
  • respiratory system
  • circulatory system
  • lymphatic system
  • endocrine system
  • reproductive system