Organs are discrete structure made up of more than one tissue, most are made up of all four ( epithelial, connective, muscle, nervous ).
Organ systems are:
- Integumentary ( skin )
- Skeletal ( bones )
- Muscular ( muscles )
- Endocrine ( glands )
- Cardiovascular (heart, arteries, veins, blood system )
- Lymphatic ( wbc transport, interstital fluid removal )