Chapter 12. The Human Body
The human body is organized from cells to tissues, organs, organ systems and the whole organism [10][11].
| System | Main role |
| Skeletal | Support, protection, blood-cell production |
| Muscular | Movement |
| Circulatory | Transport of blood, gases and nutrients |
| Respiratory | Gas exchange (oxygen in, carbon dioxide out) |
| Digestive | Breaking down food and absorbing nutrients |
| Nervous | Rapid signalling and control |
| Endocrine | Hormonal regulation |
| Immune (lymphatic) | Defence against disease |
| Excretory (urinary) | Waste removal and water balance |
| Reproductive | Production of offspring |
| Integumentary | Skin, hair and nails; protection |
Homeostasis is the maintenance of stable internal conditions through feedback mechanisms, such as regulation of body temperature and blood sugar.
Health. Balanced nutrition, regular physical activity, sleep, vaccination and hygiene support health. Infectious diseases are caused by pathogens (bacteria, viruses, fungi, parasites); non-infectious diseases include many heart conditions and cancers.
Medical advice. Information in textbooks is general. Anyone with a health concern should consult a qualified health professional.
Review: Name the organs where gas exchange occurs. (Answer: the lungs, in the alveoli.)