What is the difference in organs and an organ system ?

Question: What is the difference in organs and an organ system ?
- Keywords:
  organ,
  system
Asked by Claudiamanto to Eoin, Ester, Ildiko, Natasha, Paul, Tom on 8 Nov 2017.
- Ester Gil Vazquez answered on 8 Nov 2017:
  
  Different types of cells form tissues, and these tissues can arrange themselves in a particular way to for organs. Systems are a combination of these structures that have a common function. For example, the nervous system is formed by the brain, the spinal chord, all the nerves that connect these to the different parts of the body and, finally, the sensitive organs. All these parts work together. For example, when we eat, we taste things with the tongue (sensory organ), and this is transmitted through the nerves to the brain, which is the organ which actually processes this information to make you aware that you are tasting something.
- Paul McKeegan answered on 9 Nov 2017:
  
  Similarly the reproductive system is made up of several organs; the ovaries, oviduct, uterus, vagina and technically also the mammary glands and the brain for hormones and signals in women. In men, its the testes, epididymis, prostate and penis, and also the brain for hormones and signalling. These all count as different organs but work together as an organ system.

Question: What is the difference in organs and an organ system ?