| System | Central Unit | Input (Peripheral Unit) | Output (peripheral Unit) |
|---|---|---|---|
| Circulatory system | Heart | Vessels (arteries and veins) | |
| Digestive system | Stomach | pharynx , intestines | |
| Excretory System | Kidneys | ureter , urinary bladder | |
| Male reproductive system | Testis | epididymis , vas deferens | |
| Female reproductive system | |||
| Nervous System | Brain and spinal cord | sensory nerves and motor nerves | |
| Lymphatic system | primary and secondary lymphoid organs | lymph vessels | |
| Skeletal System | Axial skeleton | Appendicular skeleton | |
| Endocrine system | Pitutary gland | thyroid , pancreas | |